Fiberglass water/weather proof on back of wood siding

[nevets81]

I'm considering using this application to keep rainwater out of my wood sided house and give the structure a bit more strength. Would there be any adverse affects. The inside wall will be cover with one layer 8mm fiber cement board and one layer of 9mm gypsum/particle board for soundproofing. Any advice or suggestions would be appreciated.

[cheeryble]

Don't see any reason why not.

 

I turned a narrow flat roof into an upstairs balcony in England, ripping off the old zinc and replacing with GRP. Also have repaired parquet and loose substrate by injecting through small holes, saving ripping up the parquet. Perfect. Not so strong as epoxy and slight shrinkage, but plenty strong enough.

You need to do a  few tests to get the amount of catalyst right according to the temperature for convenient working time.

 

If in CM there's a supplier nearly opposite the ex British consulate same side as Ben and Jerry's.

 

[nevets81]

Thanks for that Cheeryble. I'm in rural Bangkok.

 

I'm not familiar with this process, so I'm not sure what you mean by "You need to do a few tests to get the amount of catalyst right according to the temperature for convenient working time." Can you explain?

 

 

[Crossy]

Similarly to the under-roof PU foam "solutions", many swear by them, others have nightmares.

 

The real issue with this, and other similar treatments, is that it is permanent, once it's on, it's on. No easy popping off a board that the rot has gotten at.

 

If your siding is in perfect condition then maybe, but if it needs "a bit more strength" then maybe look at other, less permanent, vapour barriers.

 

 

[nevets81]

Thanks a lot Crossy. I was hoping you would chime in, as I have read so many great posts by you over the past few months. Permanency was a concern of mine. The wood is reclaimed old golden teak, put up as lath siding. A bit battered, but not likely to split because of it being green. Still in years to come, I would like to be sure strong storms do not force water in.

 

The main issue here, is the siding is already up, so placing a vapour barrier between siding and wood studs is not possible. Hence the reason to go with gypsum on top of smartboard for the interior wall; smartboard being a bit more tolerable to moisture/water and gypsum board being more easy for finishing. The ceiling will be hung gypsum, no rolled insulation on top. We will see how the system works and then roll some out later if we deem necessary. These three bedrooms will have split AC units. I am not sure about using batten fiberglass (coolwall?) insulation between the studs. Some say air flow in the walls is important.

 

I would assume a vapour barrier between wood studs and the smartboard/gypsum wall would be less than ideal, but I am not certain of that. Your thoughts? Can a vapour barrier be placed there? If so, what material do you recommend? Simple polysheets? Tyvek does not seem readily available.

 

The double layer interior wall is also meant to provide a barrier to loud noisy neighborhood parties (perhaps green glue between). Some suggest having three layers of drywall for sound proofing. I may add another later, if needed.

 

I recently found this fiberglass application and wonder if it may be the solution.

 

[cheeryble]

Sorry I did this earlier but it didn't get posted. Some now redundant but it will answer your questions about GRP a bit:

 

Crossy has a point.

 

When u say the water's coming in.....is it because of brittle cracked weatherboards? Not enough roof overhang?

 

If the wood's in irreparable condition you might consider replacing with Shera weatherboarding.

 

If you think GRP's best for u well polyester resin unlike epoxy is catalysed by drops from a small bottle.

You want a convenient working time while the mix is still runny. But you don't want it to stay runny obviously.

The more drops the faster it goes off (becomes stiff then hard).

The higher the temperature the faster it goes off.

So you need to experiment so you can do a convenient section of the work before stiffening but so it doesn't make runs downwards.

It's not so bad.......when working with epoxy it's an exothermic reaction and the heat produced actually makes the mix go off faster sometimes so high a temp as to be dangerous and it can go off almost instantly.....not only dangerous but expensive.......you need to mix on a tray in a thin layer so the heat is dissipated.

Happily GRP's much cheaper and easier.

 

Edited April 23, 2018 by cheeryble

[nevets81]

Cheeryble, thank you for getting back to me.

 

The siding is re-milled teak from two houses we tore down and moved legally, from Lopburi to our site in east Pathum Thani. There are small holes in the siding that will be patched/filled before being coated both inside and out. I'm concerned with weathering (cracking) over time and feel this technique may be the answer to longevity. In this case, future cracks would be treated from outside, but I assume the fiberglass interior would help the siding hold up reasonably well. Re-siding with fiber concrete siding is not an option at this point. If this siding does not hold up well, in a few years we may have to tear it all down (possibly replaced with qcon). So teak it is!  The house is raised, on cement columns and beams. We have a 1 meter roof overhang. 

 

If another form of barrier can be placed between studs and interior wall, I may go that route, but I am considering whether this technique may be a better option.

 

[cheeryble]

I am well acquainted with old teak and in fact if it is thin boarding (it is often very thin) and brittle you have no chance of reboarding with the old boards many or most will split.

 

So if you want to keep the teak.......and why not?.....perhaps your GRP idea could work. if for any reason it got iffy after a few years......and with a good roof overhang I don’t see why..... you could THEN board with SHeraboard over both teak and GRP backing, just screw it on through to the studs without removing anything. Cheap and quick.

The one thing I personally would not use is the fake wood grain type of SHeraboard, better the plain surface just painted, but I’m just fussy.

 

But no reason why it should ever come to that.

 

BTW teak is of course good depending which cut of the tree it is but is not necessarily 100% rot and mite proof. You might consider a good splash of borax solution......cheap and harmless.....on the inside especially to soak down under the stud bottoms before the GRP

 

 

ps mini rollers are good for application of polyester resin

 

 

Sent from my iPad using Thaivisa Connect

 

 

[Crossy]

I'm absolutely no expert on these things, as a Brit we build very few wooden homes. The more I look the more important air circulation behind the siding appears, it's vital your siding does not remain wet, even teak will succumb to the rot if it's damp all the time.

 

Some interesting ideas here http://www.finehomebuilding.com/2016/05/17/insulating-walls-no-sheathing which shows felt paper spaced back from the siding by 15-20mm before spray foam or rigid poly sheet insulation / sound deadening.

 

 

You're not far from us in Pathum (we are near Chiang Rak Yai) why not drop round for a beer? PM me for location.

 

 

[nevets81]

You guys are making great suggestions. Greatly appreciated.

 

Where can I purchase the felt. It almost looks like what we refer to as "tar paper" in the US. Will it be eaten up by rodents? My builders most likely don't have a clue where to get it.

[nevets81]

Cheeryble, 

 

Can I PM you? 

 

[cheeryble]

4 hours ago, nevets81 said:

Cheeryble, 

 

Can I PM you? 

 

sure