New roof advice

[Kwasaki]

24 minutes ago, Sheryl said:

1...Let me see if I am following this correctly: Put the radiant barrier atop the purlins  and use  "top hat spacers" to both affix them and create a small space between them and the roofing,

 

2.  is that correct? Is that going to be enough free space?

 

3.  Several dealers of  metal sheet like blue-source color-bond, offer to pre-fix insulation with radiant barrier. glued directly to the metal sheets. 

 

4.  I question its effectiveness since there would not then be a void between the roof material and the barrier but rather foam. but can you all confirm/comment?

 

5.  Still debating fiber cement vs color-bond vs non-blue-cope brand "galvalume" which seems to be the same thing?

 

6.  company is KSS Thailand which seems also to go by the name SKC Thailand, specs attached. Anyone have any experience with this last? 

 

7.  One other question: does anyone know if rats will eat (1) EPE and (2) fiber glass insulation? I do not mean eat through it to get somewhere - they will do that with ANYTHING in my experience,

 

8.  they won't need to in order to get to my attic as they have other ways in through the eaves and vents, and rather than try to seal those up (a hassle and might impede air flow)

 

9.  I prefer to stick with my current system which is just to put one of my cats up in the attic from time to time. I mean will they eat it as food? Because if so neither will last long.

 

10.  Thanks!

 

11.  roof sheets metal SKC.

Lets break this down and make it methodical .  

1.  Yes.

2.  50 mm high spacer, the corrugated profile provides air-flow to.

3.  Personally a good idea to reduce heat but it falls off gradually.

4.  OK for a single skin outdoor situation but IMO not for house roof.

5.  The choice is yours all suitable without pre-fix insulation.

6.  If your saying will (with) it last, yes from experiencing use in UK if the spec is the same, galvanized metal sheeting with coloured coatings have lasted some 40 years or more, that said there is as always a maintenance factor involved the same with any roof product used.

7.  Rats ?  no idea never known them to eat fibre-glass or rock-wool, nest in it maybe, precautions have always been taken in most roof constructions one way or another.

8.  Venting roof spaces correctly is usually adequate for most ingress of roof pests.

9.. Yeah l've seen rats eating cats. 

10.  Your welcome. 

11.  Usual type of ad for most roof products showing there product range, what's important is spec & guarantees.

 

[simoh1490]

Not intending to cut across kawasaki and his experience, some clarification on two points:

 

Regarding number 2 above.

 

The space between the radiant barrier and the roofing material is not so much about airflow, it's only about ensuring there is a continuity break between the two surfaces. A piece of steel radiates heat, if I put a piece of aluminium foil against the steel the aluminium foil will radiate heat since one surface becomes a continuation of the other and for heat transfer purposes they are seen as a single surface. But if there's a gap between the two materials they become separate surfaces and since a radiant barrier is not able to store heat it cannot radiate it onwards.

 

Regarding number 3.

 

If the afixed foam insulation is EPE it is nothing more than air bubbles wrapped in plastic, not too different in concept from bubble wrap except the bubbles are very small. Since air is not an insulator and plastic is not either, we hope it's not EPE but rather PU foam which is very dense and a good insulator. EPE foam PU foam, not part of the average rats normal diet.

 

[bankruatsteve]

32 minutes ago, simoh1490 said:

Since air is not an insulator ...

I couldn't get out of the quote and somehow posted this 3 times.  ????

 

Anyway... air is actually a good insulator is what I wanted to say.

 

[simoh1490]

10 minutes ago, bankruatsteve said:

40 minutes ago, simoh1490 said:

Since air is not an insulator ...

 

Trapped air in sufficient quantity can be a thermal insulator, as in a cavity wall, but moveable or free standing air is the basis of convected heat and bubbles in EPE foam are so small as to be ineffective as an insulator against heat.

 

EDIT TO ADD: Almost any product such as PE foam CAN act as a thermal insulator IF it is thick enough, the same can be said of almost any product not commonly regarded as insulation. But foil faced PE foam is less than 5 mm thick and tests have proven (see above video) that it itself is not an effective barrier against heat penetration. I suppose if the PE foam is three inches thick it would begin to show some characteristics of a thermal barrier, not that the composition of the foam will have changed, simply, the density of it will begin to retard heat transfer. 

 

[simoh1490]

I may stand to be corrected on the air gap issue but my jury is still out, the link below provides a good description of the radiant barrier installation process and suggests drooping the barrier between the rafters to allow for a 1 inch gap: https://energy.gov/energysaver/radiant-barriers

[Kwasaki]

4 hours ago, simoh1490 said:

installation process and suggests drooping the barrier between the rafters to allow for a 1 inch gap:

 https://energy.gov/energysaver/radiant-barriers

25 mm is minimum.

Government hype many ways to keep roofs cool. 

[simoh1490]

25 minutes ago, Kwasaki said:

25 mm is minimum.

Government hype many ways to keep roofs cool. 

I'm inclined to agree, it's not an issue of how much space, it's more about that the two surfaces don't touch, 25 mm sounds safe and reasonable to me.

[Sheryl]

Thanks everyone especially Kwasaki and Simoh, and Ahab who has given a lot of offline tips.

 

In addition to all the very helpful replies here I have been in email contact with Bluesource company, a Khun  Kasem there has been very patient in answering my questions, and also had a long chat with KSS / SKC company which turns out to have an expat named Simon working for them so great chance to get info in English (and it also turns out that they can order bluesource if preferred to their usual product), and I have visited one Blusource dealer in person and tomorrow will call 2 others that I have leads on that have English speaking staff.

 

On the subject of applying the radiant barrier + foam directly to the metal sheet the feedback I got from Bluesource company - who have no stake in the issue either way as they are not a dealer and do not sell the insulation or barriers - -  is as follows

 

(1)  won't help much if at all for the heat because, as we have all surmised, lack of space between the barrier and the roofing  

 

(2) will help with the noise initially but so would insulation batts laid down on the ceiling, along with using maximum thickness metal sheet (0.50)  AND

 

(3) falls off within 1-2 years. 

 

The last point  to me is absolute clincher. So: metal sheet without insulation, add radiant barrier and put down batts, it shall be. I am opting for the metal sheet because general consensus seems to be that it lasts longer and is cooler. It will however cost significantly more than tiles, but coolness and not having to do another roof replacement in my old age are higher priorities than current cost. I have also verified that it will come in pre-cut panels, width .76m and length whatever the length of the rook requires, so installation by workers used to tiles should not be big problem (it is possible the most experienced roofer in the group has experience with zinc roofs back in Cambodia , I have to check on that).

 

Remaining issues at this point are:

 

(1) Buy Bluesource brand or get the china-made galvalume sold by KSS / SKC. Product brochure indicates identical specs so I think it comes down to, does one trust the stated specs of this  Chinese manufactured product. They do not offer a warranty the way Bluesource does. I am not so much concerned to have the warranty per se -- no doubt all manner of fine print that might get in the way of having it honored and the whole point as far as I am concerned is to not need  to try to enforce a warranty - but it tells me they have true confidence in the longevity of their product. I have so far not been able to get any first hand reports from people on using non-blusource brand galvalume. But the cost difference is large. By my reckoning I have about 280 sq meters to cover not counting top pieces, and bluesource would cost about 64,000 vs generic galvalume about 42,000. (Fiber cement by contrast only about 22,500 for the flat pieces, would have to add on the special sized top and corner peices which are more costly but still I expect would come in at under 40,000.)  I will get price quotes from 2 more Bluesource dealers tomorrow but so far those I have spoken to have been pretty consistent at around 220 baht per sq m.  which was also the estimate of the parent company.

 

(2) How to affix the radiant barrier: I went shopping for radiant barrier, insulation batts and top hat spacers today. Readily sourced the first two, the top hat spacer, despite showing pictures  set off a chorus of "mai mees". I don't really believe them (this was at DO Home in Thanyaburi which is huge and has most everything), more likely just didn't recognize from the pix and didn't want to bother,  but I was also unsuccessful in spotting anything like it on the shelves on my own, though in the process I saw a number of other things that looked like they'd work so am thinking to just convey the concept to the workers and let them come up with a solution.

 

(3) How much overhang to have on the metal sheets...I would like maximal to better shade the windows below on the sides of the house, which face east and west respectively (house itself faces south). I don't know the length of my current overhand but it is not much. Simon at KSS/SKC said most people leave about 20-30 cm but he didn't see any reason why it couldn't potentially be more..however we get torrential downpours where I live, I mean seriously torrential,  the solid sheet of rain type and much more often than elsewhere in country (I am on the immediate southside of Khao Yai.  Issan is dry because the rain doesn't make it over the mountains - it comes in from the coast and gets as far as where I live and all comes down there!)  That rain will exert a lot of downward pressure. Also loose overhang might increase chance of wind ripping off the sheet? (And we occasionally get gale force winds here, the kind that uproot large trees and damage roofs). Plus when I examined the stuff at the dealer it looked to me like it would flop down pretty readily if overhanging the purlins by much - but I would like to hear other people's thoughts on that. I will need to know this to decide on length to order.

 

Re the radiant barrier and batts, I bought some but not all I will need - would never fit in my car! - but would like some thoughts on whether I got the right ones as there was a dizzying area of choice.:

 

Foil - NASH "Cool" brand, 2 ply. Says something or other 95% on it. 1,456 baht for 1.25 x 60 meters

 

Batts:  some brand with a penguin on it, 3" microfiber Rt = 21 which was the highest they had. 181 baht fir ,5 x 4 meters.

 

Cost around 6,000 baht for quantity less than 1/4 my needs so the insulation + radiant barrier are going to come to around 25K, but my electric bills currently except in the coolest months range 5-7,000 so I am hoping even a modest reduction will pay for itself within a few years.

 

 

 

 

 

[simoh1490]

Falls of in 1 - 2 years! Makes sense since the expansion and contraction of the steel is likely greater than that of the attached foam.

 

Top Hat Spacers: In my roof these are three or four metre lengths and are very inexpensive to buy. They are not angular and the top hat is not well defined, instead, the corners are much more rounded, the profile of the metal is one of a flowing undualating series of curves, think an extended S shape profile - I'll try and post a picture of some in the morning.

 

Foil price sounds right, insulation is cheaper than most. You'll need a couple of rolls of silver foil tape to fix any tears, it comes in rolls that are about two inches wide or more and it's not cheap.

 

Your observations on the overhang are spot on, you shouldn't overhang an unsupported product by very much or it will do all the things you suggest it might - be careful about trying to redefine the design of your roof with steel sheets alone, it could have unintended consequences!

 

Trusting the Chinese specification is the major issue, from the product reviews below galvalume is a good product but can you trust the manufacturing and quality control processes, perhaps the distributor could be probed on this point. Some very good end user reviews of galvalume below, consumers also compare the two types of roofing and it's hard to tell which is actually the best! 

 

https://www.garagejournal.com/forum/showthread.php?t=247800

 

Positive reviews of galvalume here - https://www.improvenet.com/r/costs-and-prices/galvalume-roofing

 

 

 

[carlyai]

Falls of in 1 - 2 years! Makes sense since the expansion and contraction of the steel is likely greater than that of the attached foam.
 
Top Hat Spacers: In my roof these are three or four metre lengths and are very inexpensive to buy. They are not angular and the top hat is not well defined, instead, the corners are much more rounded, the profile of the metal is one of a flowing undualating series of curves, think an extended S shape profile - I'll try and post a picture of some in the morning.
 
Foil price sounds right, insulation is cheaper than most. You'll need a couple of rolls of silver foil tape to fix any tears, it comes in rolls that are about two inches wide or more and it's not cheap.
 
Your observations on the overhang are spot on, you shouldn't overhang an unsupported product by very much or it will do all the things you suggest it might - be careful about trying to redefine the design of your roof with steel sheets alone, it could have unintended consequences!
 
Trusting the Chinese specification is the major issue, from the product reviews below galvalume is a good product but can you trust the manufacturing and quality control processes, perhaps the distributor could be probed on this point. Some very good end user reviews of galvalume below, consumers also compare the two types of roofing and it's hard to tell which is actually the best! 
 
https://www.garagejournal.com/forum/showthread.php?t=247800
 
Positive reviews of galvalume here - https://www.improvenet.com/r/costs-and-prices/galvalume-roofing
 
 
 

If you look at the toilet roofs when you go there, after stopping to fill up your gas tank, you will see the insulation has fallen off.
This was a worry to me building the shed and pool roof. The local company I bought mine of has a 10 year guarantee....so changed my mind. Shed now over 3 years and no sign of insulation falling off.

I'm pretty sure the manufacturer of my radiant barrier (seems like the double sided one you are thinking of Sheryl) said 2" air gap.

As an off topic comment on bats, the outback dirt bush airport where I worked had a wire fence around it to stop the kangaroos/crocodiles etc. On the top of the fence there were 2 strands of wire about about 40 cm apart and the bats used to get stranded on the wires...maybe their radar couldn't see the wires. This could be a way of keeping some out of your place.

Sent from my SM-J700F using Tapatalk

[simoh1490]

Just a thought - if you want the roof to overhang the windows more than at present, why not attach additional steel and extend the roof by the amount you want. If you wanted a further metre of overhang you'd probably need to add two metres of steel, which could easily be welded on, not a major job really and not very expensive - last time I looked box steel for that kind of job was 367 baht for four metres and you don't have a high concentration of roof beams hence not that many needed. If you consider doing that, check and make sure the garden can handle the rainwater from the roof because the point where it leaves the roof will have changed, unless you have gutters that is.

 

Forget the above, I just looked at the picture of your house, you might just manage a 20/30 cms additional overhang but your roof is already extended far enough, perhaps try hanging bamboo curtains from the roof to shield specific window, they work well.

[simoh1490]

Another thought - when concrete roof tiles are laid on a roof, the first course is at the edge of the roof and most roofers install a black plastic/PVC strip that has the same profile as the roof tile but has holes in it so that air can pass through it and up into the roof void. The purpose of the strip is to block the gap under the tile and to keep vermin out of the attic space, it's very inexpensive to buy and simple to install. 

 

I presume that sheet metal roofing has a similar strip that serves the same purpose, I doubt however that your existing roof has one installed hence your current rat problem. Install the strip and your pest problem may well disappear, your supplier will be able to identify the product easily I imagine. 

[simoh1490]

And yet Another!

 

Now that I've studied the picture of your house on the first page, can I suggest you read again my post number 54 which talks about attic/roof void ventilation? The reason I think that's important is that I now see that you have some amount of hot air venting in the gables of your roof, the square grills are fine but they could be larger and or more of them. The absolutely key point however is that there is no cool air intake other than the nooks and crannies you've mentioned and frankly that's not going to add up to very much in total square feet. Typically in that design of house (and your overhanging roof is identical to mine), the eves boards or area under the overhang of the roof would be slotted or vented rather than solid, that is the primary means for introducing cooler air into the roof. Vented/slotted  eves boards are cheap, I replaced all of my solid boards with slotted ones for under about 4k baht, I replaced some of them myself but then paid someone 2k to finish the job. 

 

The reason the above is very important is that you've said your house has a heat problem currently and your existing roof is made of a material that has some insulating properties. Your new steel roof has no insulating properties and whilst you are planning to instal R16 batt insulation on the attic floor (which will solve any acoustical problems) it is very likely to be defeated by the heat quite quickly. This is because the hot air in the roof void has nowhere to go other than downwards into the living space. I think it's important to clearly separate solutions for roof surface covering, acoustic insulation and thermal insulation/ventilation because they all have slightly different requirements and present different challenges. I think what you've decided on thus far is very good but I'd wait and see how the heat issue is, once the roof is on and the attic floor insulation laid - if it's still hot inside the house, replacing the eves boards will be an essential step.

[Sheryl]

Very clear, thanks. I will discuss with the work crew. It looks to me like the current eaves board is a thick wood plank but that is looking from a distance so I'm not sure, nor do I know how easily it could be removed.

 

Re the top hat spacer, discussed with worker yesterday and he suggested to use the thin (?aluminum?) frame things used to affix ceiling board to....putting that on the inside of the rafters and purlins. We could I suppose also reverse that and put it atop the purlins so that it is between the roofing and the purlins and barrier but then the questions is whether it would be  be strong enough to support the roofing as those frames are thin and easily bent. Whereas it can surely support the foil. It's cheap and easy to source. Makes sense to me, your thoughts? It would mean having to affix the aluminum barrier with screws, does that work well or does the stuff tear? What I have seen online has been stapling but that only works if affixing to wood.

[simoh1490]

The eves boards are most likely to be fibre cement panels that are half a cm thick. The slotted/vented panels are the same size and cost around 100 baht each as I recall but must be fixed using special screws (that are also cheap). I used an angle grinder and cut my eves boards out, it's easily and quickly done.

 

See below picture of the tophat channel you can use, your builders will almost certainly recognise it, it's very lightweight and strong - the thin aluminium you describe makes me nervous hence I'm unsure. If you use the below (or whatever you use) lay it on top of the radiant barrier so that the fixing strip is facing towards you and fix both the RB and the strip together, drilling/screwing through both. If you try to fasten the RB without some sort of outer fixing strip it will rip, think of the fixing strip/top hat as a huge washer that holds the RB in place.

 

Me, I would fasten it as follows: lay the RB directly across the roof beams in overlapping horizontal rows. Next, afix the top hat on top of the RB and screw them both onto the roof beams. Third, lay the steel panels on top of the top hat and screw it into the top hat. 

 

 

 

 

[simoh1490]

This is what slotted eves boards look like - also note the use of bamboo curtains to shield key windows from the sun, they are very very effective:

[carlyai]

Another thought - when concrete roof tiles are laid on a roof, the first course is at the edge of the roof and most roofers install a black plastic/PVC strip that has the same profile as the roof tile but has holes in it so that air can pass through it and up into the roof void. The purpose of the strip is to block the gap under the tile and to keep vermin out of the attic space, it's very inexpensive to buy and simple to install. 
 
I presume that sheet metal roofing has a similar strip that serves the same purpose, I doubt however that your existing roof has one installed hence your current rat problem. Install the strip and your pest problem may well disappear, your supplier will be able to identify the product easily I imagine. 

In my experience, roofers do not automatically install the wavy plastic strips to stop vermin, you have to do it yourself, well in Isaan you have to ( I may be corrected). They do not stop all the pests like those small birds, who love to squeeze through and nest in the roof. Another poster said you need the plastic thinggies plus No-More-Gaps.

Sent from my SM-J700F using Tapatalk

[simoh1490]

20 minutes ago, carlyai said:

In my experience, roofers do not automatically install the wavy plastic strips to stop vermin, you have to do it yourself, well in Isaan you have to ( I may be corrected). They do not stop all the pests like those small birds, who love to squeeze through and nest in the roof. Another poster said you need the plastic thinggies plus No-More-Gaps.

Sent from my SM-J700F using Tapatalk
 

They are difficult if not impossible to retrofit snugly, far easier and simpler to fit them as the roof is being laid.

[simoh1490]

Important also to remember to leave a gap between the radiant barrier and the ridge of the roof so that the hot air can vent into the roof void/attic, do not carry the RB all the way to the ridgeline of the roof - a one foot gap on both faces of the roof, left uncovered by the RB will work fine for this purpose.

[carlyai]

They are difficult if not impossible to retrofit snugly, far easier and simpler to fit them as the roof is being laid.

Yes I would agree, but you have to buy them and get the roofers to do it at the same time, I don't think they install them as part of the roofing job. It's just money, if they install them as the roof goes on it will cost more.

Sent from my SM-J700F using Tapatalk

[simoh1490]

Here's a couple of pictures of my roof void that were taken last year before the work was completed. Note the radiant barrier on the inside of the roof, tacked onto the stell with bolts and washers (not ideal but no other choice at the time). Note also the top hot that roof tiles sit on, imagine your RB sitting between the top hat and the roof beams, a much better arrangement. Finally, note the attic floor insulation with electrical conduit on top.

[simoh1490]

3 minutes ago, carlyai said:

Yes I would agree, but you have to buy them and get the roofers to do it at the same time, I don't think they install them as part of the roofing job. It's just money, if they install them as the roof goes on it will cost more.

Sent from my SM-J700F using Tapatalk
 

I think a box of the plastic strips is around 230 baht and you'll need around four boxes if memory serves - personally, I'd just hand them to the builders and say here, you'll need these! Of course, you may also have to show them what they are for !!!

[Sheryl]

Lots more information, thanks!

 

1- Eaves boards: I had not understood what they were and had them confused with the beams (thick wood I think but could be metal) that form the outer roof ridge.  I see now what you mean are the boards that run parallel to the roof on the underside of the purlins, mine seem to be 1m x 2 m and yes, looks like some kind of fiber board. I would need about 26 of these boards but if they really cost only 100 baht each that is fine (seems awfully cheap?). 

 

2 - Top hat: that also, I had misunderstood to be a smaller gizmo rather than the channel.  I have something like what you show here serving as purlins to support roofing over the outdoor staircase of small house I built for household staff next door to mine. SO the idea is to put this on top of the purlins with the RB between the two? And when you say fixing strip you mean the middle part? So that it is installed looking like a right-side up hat, and the two side parts  (hat brim) are what fastens to the RB, while the roofing fastens to the raised part? I guess this means it must be same width or less than the purlins?  Any idea what these top hat channels cost? If I do it that way I will need quite a lot of it since in order to have adequate support for the roof will need to cover all purlins. Whereas if we affix the RB to underside of the purlins and rafters with the RB between, only need to use enough (whether of top hat channel or aluminum strips or whatever) to keep the RB in place as not supporting any weight.  So both less cost for materials and less work/time to do. How much difference will it make if done that way and thus allowing rafters to heat up?

 

3 -  Wavy plastic strips: Is it something like this?

 

 

And install how/with what?  Does it just snap into place? Reading online all the sites seem to talk about foam but I think that would be for temperate climates? Anyone have a picture of the boxes sold in Thailand or know brand name?

 

4 - No-More-Gaps: Is this sold in Thailand? Or can I just use silicone?

[simoh1490]

58 minutes ago, Sheryl said:

Lots more information, thanks!

 

1- Eaves boards: I had not understood what they were and had them confused with the beams (thick wood I think but could be metal) that form the outer roof ridge.  I see now what you mean are the boards that run parallel to the roof on the underside of the purlins, mine seem to be 1m x 2 m and yes, looks like some kind of fiber board. I would need about 26 of these boards but if they really cost only 100 baht each that is fine (seems awfully cheap?). 

 

2 - Top hat: that also, I had misunderstood to be a smaller gizmo rather than the channel.  I have something like what you show here serving as purlins to support roofing over the outdoor staircase of small house I built for household staff next door to mine. SO the idea is to put this on top of the purlins with the RB between the two? And when you say fixing strip you mean the middle part? So that it is installed looking like a right-side up hat, and the two side parts  (hat brim) are what fastens to the RB, while the roofing fastens to the raised part? I guess this means it must be same width or less than the purlins?  Any idea what these top hat channels cost? If I do it that way I will need quite a lot of it since in order to have adequate support for the roof will need to cover all purlins. Whereas if we affix the RB to underside of the purlins and rafters with the RB between, only need to use enough (whether of top hat channel or aluminum strips or whatever) to keep the RB in place as not supporting any weight.  So both less cost for materials and less work/time to do. How much difference will it make if done that way and thus allowing rafters to heat up?

 

3 -  Wavy plastic strips: Is it something like this?

 

 

And install how/with what?  Does it just snap into place? Reading online all the sites seem to talk about foam but I think that would be for temperate climates? Anyone have a picture of the boxes sold in Thailand or know brand name?

 

4 - No-More-Gaps: Is this sold in Thailand? Or can I just use silicone?

8

1 - Sorry I lied, they're not 100 baht they're 44 baht each at Homepro, they'll be cheaper elsewhere - https://www.homepro.co.th/product/1032833

See below a picture of a vented eves board, both sides, if you use them I strongly recommend you buy a roll of wire mosquito mesh, cut it to size and glue/fasten it on the back of the board, that way the nasties can't get in and and nest etc. It's easy enough to do but it's a bit time consuming and fiddly.

 

2 - SO the idea is to put this on top of the purlins with the RB between the two? - YES

And when you say fixing strip you mean the middle part? So that it is installed looking like a right-side up hat, and the two side parts  (hat brim) are what fastens to the RB, while the roofing fastens to the raised part? - YES

I guess this means it must be same width or less than the purlins?  You lost me! The top hat is fastened to the roof beams parrallell to the eves, in other words they run across the beams rather than in the same direction as them, clear?

Any idea what these top hat channels cost? - no but cheap, 30 baht maybe, can't remember.

 

3 - plastic wavy things (!) no, not even close. Imagine a flat piece of black plastic, flat on the bottom, wavy or contoured to the shape of the roof tile on the top with cut out shapes to let air through in the middle - maybe an eighth of an inch thick, rigid but somewhat flexible. They are fixed at the eves under the roof where the first sheet/tile overhangs the roof, they are screwed onto the wooden fascia board where the roof meets the wall - if no fascia board, easy enough to fix other ways including fastening to the underside of the roof material. I'll try find a picture. No brand name, it's just stamped plastic and not sophisticated enough to be branded.

 

4 - No More Gaps - Forget what I wrote, I was being flippant rather than describing a product, sorry, .

 

 

[simoh1490]

Here's a UK site that shows bunches of the plastic thingies, apparently they are called eave's fillers although being the UK they are really expensive plus I don't see the one that's typically used in Thailand - your roofing supply guy will know: http://www.ebay.co.uk/bhp/eaves-filler The ones you are looking for must have the same contour as the roofing material you are going to use.

 

EDIT - last picture, bottom right, they come in strips and are boxed, but these are for concrete tiles, not steel roofs.http://www.coolthaihouse.com/origCTH/inforoof.htm

[Sheryl]

1 hour ago, simoh1490 said:

1 - Sorry I lied, they're not 100 baht they're 44 baht each at Homepro, they'll be cheaper elsewhere - https://www.homepro.co.th/product/1032833

See below a picture of a vented eves board, both sides, if you use them I strongly recommend you buy a roll of wire mosquito mesh, cut it to size and glue/fasten it on the back of the board, that way the nasties can't get in and and nest etc. It's easy enough to do but it's a bit time consuming and fiddly.

 

2 - SO the idea is to put this on top of the purlins with the RB between the two? - YES

And when you say fixing strip you mean the middle part? So that it is installed looking like a right-side up hat, and the two side parts  (hat brim) are what fastens to the RB, while the roofing fastens to the raised part? - YES

I guess this means it must be same width or less than the purlins?  You lost me! The top hat is fastened to the roof beams parrallell to the eves, in other words they run across the beams rather than in the same direction as them, clear?

Any idea what these top hat channels cost? - no but cheap, 30 baht maybe, can't remember.

 

3 - plastic wavy things (!) no, not even close. Imagine a flat piece of black plastic, flat on the bottom, wavy or contoured to the shape of the roof tile on the top with cut out shapes to let air through in the middle - maybe an eighth of an inch thick, rigid but somewhat flexible. They are fixed at the eves under the roof where the first sheet/tile overhangs the roof, they are screwed onto the wooden fascia board where the roof meets the wall - if no fascia board, easy enough to fix other ways including fastening to the underside of the roof material. I'll try find a picture. No brand name, it's just stamped plastic and not sophisticated enough to be branded.

 

4 - No More Gaps - Forget what I wrote, I was being flippant rather than describing a product, sorry, .

 

 

 

1 - Wire mosquito mesh comes in rolls?  Any idea what it is called in Thai or any pix of it? I have never seen it and in fact at times resorted to cutting up mosquito nets when the mesh was what I really needed. As this is turning into a lot of work, what do you think of not replacing all the eaves boards but just some on each side of the house?

 

2 - Unfortunately no not all at clear. When you say beams do you mean the rafters or the purlins? To my understanding the metal beams that run vertically are rafters and the horizontal ones are purlins.  Normally would attach the roofing to the purlins (beams that run parallele to the eaves, at 1 meter inervals and attacged to the rafters) . If going to use top hat channel  affixed at bottom to  RB and on top to the roofing then it surely needs to run the whole  length of all the purlins, doesn't it? Otherwise may not be sufficient support for the roofing panels. And in order to attach to the purlin would need to not be wider than it. OR am I missing something? If used under the beams solely to affix the RB, with the roofing attached to the purlins as usual, then can use far fewer on them because no need to also hold the weight of the roof.

 

3- Plastic thingies: My roofing guys do not know and I am also having trouble communicating  what it is I need to the roofing suppliers. Please someone, tell me what is it called in Thai? Or provide a pix of it?  I wish I had known about eons ago, as you may observe on the pictures of my eaves I jerry rigged somnthing else when this is what would have been ideal, that was done due to major bat infestation, the guano of which cost me new ceilings.

[simoh1490]

33 minutes ago, Sheryl said:

1 - Wire mosquito mesh comes in rolls?  Any idea what it is called in Thai or any pix of it? I have never seen it and in fact at times resorted to cutting up mosquito nets when the mesh was what I really needed. As this is turning into a lot of work, what do you think of not replacing all the eaves boards but just some on each side of the house?

 

2 - Unfortunately no not all at clear. When you say beams do you mean the rafters or the purlins? To my understanding the metal beams that run vertically are rafters and the horizontal ones are purlins.  Normally would attach the roofing to the purlins (beams that run parallele to the eaves, at 1 meter inervals and attacged to the rafters) . If going to use top hat channel  affixed at bottom to  RB and on top to the roofing then it surely needs to run the whole  length of all the purlins, doesn't it? Otherwise may not be sufficient support for the roofing panels. And in order to attach to the purlin would need to not be wider than it. OR am I missing something? If used under the beams solely to affix the RB, with the roofing attached to the purlins as usual, then can use far fewer on them because no need to also hold the weight of the roof.

 

3- Plastic thingies: My roofing guys do not know and I am also having trouble communicating  what it is I need to the roofing suppliers. Please someone, tell me what is it called in Thai? Or provide a pix of it?  I wish I had known about eons ago, as you may observe on the pictures of my eaves I jerry rigged somnthing else when this is what would have been ideal, that was done due to major bat infestation, the guano of which cost me new ceilings.

1 - wire mosquito mesh is the same material that is used in screen doors and screen windows, it comes in rolls and is inexpensive. It can be purchased in many places including screen door/window makers but a Hompro or similar will be cheaper.

 

2 - I'm sorry my explanation didn't work, let me try and prepare a better explanation overnight and I'll post it in the early morning.

 

3 - What you're requesting may not help, I've provided a link to show the concept of the product but they are matched to individual roofing material shapes so your supplier will be the person who SHOULD know. Perhaps the question to ask them is, "what do I use to stop vermin and bugs entering my attic under the contour of your product". 

[Sheryl]

1 - I know what it is, just never found it for sale anywhere, and have looked several times in the past,  Definitley niot at my local HomePro as I know every inch of it but their stock tends to be limited compared to most HomePros.  Locla screen/window maker obviously has it but won't sell it as they make their money installing screens.  Brand name or picture of the roll might help. I suppose in worst case I just bring all the eave boards to the lcoal window/screen shop and ask them to affix the screening for me.

 

2- OK thanks

 

3- Will do

[simoh1490]

2 minutes ago, Sheryl said:

1 - I know what it is, just never found it for sale anywhere, and have looked several times in the past,  Definitley niot at my local HomePro as I know every inch of it but their stock tends to be limited compared to most HomePros.  Locla screen/window maker obviously has it but won't sell it as they make their money installing screens.  Brand name or picture of the roll might help. I suppose in worst case I just bring all the eave boards to the lcoal window/screen shop and ask them to affix the screening for me.

 

2- OK thanks

 

3- Will do

I can buy wire mosquito mesh by the metre at my local Homepro as I can other similar products - if you can't buy it easily locally I can easily and happily ship you some if required, not a problem.

 

Have to sign off now until the AM. 

[simoh1490]

Terminology:

rafters - long heavy box steel running from eaves to ridge

purlins - box steel laid across the rafters running parallel with the eaves

tophat (TH) - an alloy like channel used to create an air gap, hold down the RB and a fixing surface for the roof material.

 

Please take a look at Kwasaki post number 53 again, that shows RB laid on purlins using top hat (TH) to fasten it, and, roof material on top of the TH. That will work fine except:

 

it will raise the roof equal to the depth of the TH, this means there will be a gap at the eaves board (a strip of wood afixed to the top of the wall, under the roof) which needs to be filled by a second strip of wood (eaves board 2) - this might be a bit messy but it will work.

 

your option is to fasten the RB under the rafters on the inside of the house, this is pretty much identical to what is shown in the picture previously of my attic. It's more difficult to fix on the inside than the outside of the roof but it can be done. If you take that route don't use screws alone, use furring or fixing strips that run the length of the roof in the same direction as the purlins to hold the RB in place, you don't need to use TH for this, any lightweight but strong strip will suffice - the air gap will between the roof surface and the RB will be equal to the depth of the rafter which is good.

 

Finally, you can then lay the roof sheets on the purlins or TH based on which approach you choose to lay the RB - if you don't have a clear preference on this, perhaps ask your builder which he prefers since he has to do it, the outcome will be the same either way.