Waterproofing a wall with Rubber?

Hi guys, I'm getting close to ordering the materials in ready for my build however i have a quick couple of questions that are bugging me. My outside walls are mearly timber cladding on to 2 x 4's however - there are patches and holes in the cladding almost everywhere. What we thought was to start by running a rubber sheet along the walls following the contor of the cladding and the frame. From there insulation would go into the existing frame ONTOP of the rubber sheet. So first question - will the rubber sheet affect the mass - air - mass design? The from here there is an air gap followed by our next wooden frame with insulation, On this (the now inside wall) we were thinking of using plywood to finish - would plasterboard be better? The problem we have is that we cannot alter the outer cladding - the rubber sheet really only seems like the way to water tighten it? Many thanks, Ed

rmproduction wrote:

Hi guys, I'm getting close to ordering the materials in ready for my build however i have a quick couple of questions that are bugging me. My outside walls are mearly timber cladding on to 2 x 4's however - there are patches and holes in the cladding almost everywhere. What we thought was to start by running a rubber sheet along the walls following the contor of the cladding and the frame. From there insulation would go into the existing frame ONTOP of the rubber sheet. So first question - will the rubber sheet affect the mass - air - mass design? The from here there is an air gap followed by our next wooden frame with insulation, On this (the now inside wall) we were thinking of using plywood to finish - would plasterboard be better? The problem we have is that we cannot alter the outer cladding - the rubber sheet really only seems like the way to water tighten it?

Ed, I've never builtin the UK- but it seems to me that the climate would be calling on vapour barriers to place placed on the room side of a wall - not the outside face of a wall. If this is true in your case - then that will be the problem wth your applacation,,,,,,, thius material is a vapour barrier. Sincerely, Rod

Hi Rod, Thanks for the reply - the problem we have is waterproofing the outside wall before we begin the build - the timber cladding is patchy in places and so the rubber is to stop water leaking in. Because the building is listed we cant touch the cladding - we have to put something against it instead.

Understand that having a vapor barrier in the wrong place and the right place at the same time is really bad.

I cant seem to find any descriptions of vapour barrier usage through the forum search - can you help me out with its useage or direct me somewhere that discusses it? Many thanks, Ed

You say that the building is listed, but doesn't mean it should be left to fall apart. If there are holes in the outer cladding that let water in then I'd say that was a pretty urgent repair. As it's listed you may even be fined or whatever for not maintaining it. That aside, rubber will not be the best or most cost effective material. You may have to take the cladding off, fix a waterproof barrier and then replace the cladding onto timber battens. (Replacing any damaged with identical stuff as you go along) The best product for the job would be breathable roofing felt. This stuff keeps water from penetrating but lets water vapour (ie condensation) out, timber structures MUST be able to 'breathe' Otherwise rot and mould can set in and that's a pretty expensive repair job! Tyvek being one of the market leaders of breathable felt. If this is a studio related question then currently you have timber cladding (with holes in!) and maybe a membrane of some kind. Therefore you have zero soundproofing. What's the construction plan from the walls inwards?

Thanks for the reply deluks! - glad to know im not the only one up at this time! I'll check out the tyvek stuff - and find out about maintenance to the building (it didnt seem to come up in our meeting) Wall is going to be (so far) - the timber clad on frame (plus whatever happens to fix it) with rockwool in the frame - air gap - interior rooms (debating floating concrete floor) with framing - rockwool - plywood - plasterboard (ply and plasterboard in either combination) Do you own a studio yourself in London? Ed

Try searching for "vapor" (no "u")... There are probably more references with the US spelling. I agree that outer leaf wall, unless more beefy and sealed (yet vapor permeable), will suck for isolation. --Keith :mrgreen:

rmproduction wrote:

Thanks for the reply deluks! - glad to know im not the only one up at this time! I'll check out the tyvek stuff - and find out about maintenance to the building (it didnt seem to come up in our meeting) Wall is going to be (so far) - the timber clad on frame (plus whatever happens to fix it) with rockwool in the frame - air gap - interior rooms (debating floating concrete floor) with framing - rockwool - plywood - plasterboard (ply and plasterboard in either combination) Do you own a studio yourself in London? Ed

Not yet, I've only been planning it for about 18 months :lol: If the cladding must stay, then I'd suggest lining inside of the 4x2 framing with a couple of layers of ply/plasterboard/OSB and making this your outer leaf, then build a seperate rockwool filled frame inside the room, clad on the interior with 2or3 layers of 12.5mm plasterboard. You will reduce performance by some extend by having 3 walls, but that cladding alone will do you no favours. (favors?) :wink: Floating concrete floor = lot of money. How soundproof does it need to be? What is the size of the building/room. Any pics?

If i could refer you to a new thread i started - it will be my diary of construction and has a couple of pictures and ideas plus more information. http://www.johnlsayers.com/phpBB2/viewt ... 5c884a0041 Not sure about three leaf wall - surely there must be away of fixing some board to the inside of the cladding without damaging it! Cheers Keith will start reading all the threads that came up!

rmproduction wrote:

Not sure about three leaf wall - surely there must be away of fixing some board to the inside of the cladding without damaging it!

Not wise though, exterior timber cladding must have airflow behind it, any moisture that gets behind (and it does) needs ventilation so it can dry out properly. I honestly don't think you have a choice, but you can always overcompensate in the inner wall to make up for it, so all's not lost. 3 leaf walls aren't ideal but there are many situations where you've gotta work around it, corrugated roofing springs to mind.

So at the moment my options are to either a) remove the cladding, fix layer such a tyvek to the timber frame then refix the cladding repairing any holes (subject to permission) b)Seal over the frame with board and use that as the outer leaf. i'm not really keen on either! Deluks did you manage to check out my other thread? Bottom walls have brickon the inside - leads me to believe that that is a double leaf wall already and watertight. Ive attached the picture showing both a bit of the upstairs framing and the downstairs brick. I see a lot of problems arising with this build - i know the guys on this forum will be a great source of support and inspiration and constructual criticism! Cheers

Just had another thought - What if i used a plastic wrap as per my first thoughts (as a vaour barrier not retarder) and then install dehumidifiers in the air gap between outer and inner walls (maybe loads of silica beads as well? so rather than let the moisture excape i let it get absorbed by these? I've been reading non stop on vapour barriers/retarders and realise the importance of not letting moisture build up. If i also used the insluation i've read about that is mold/rot resistant - would this idea not be as effective? (maybe moreso as moisture is eliminated from the area rather than just left to make its way out>? I was also thinking whether or not there was any material that would prevent water entering through the cladding AND be breathable? So if any of this would work - i could wrap the plastic/material around the wood frame + cladding - reinforce the wall with plasterboard between the frame (so cladding plastic plasterboard = 1 leaf) then fill the frame with the resistant insulation?? Another thought that occured was whther it would be possible to fit tyvek or another similar material to the cladding from the inside? (i've searched the tyvek site but cant find any information on this) Cheers for all the help so far guys!! Ed

rmproduction wrote:

So at the moment my options are to either a) remove the cladding, fix layer such a tyvek to the timber frame then refix the cladding repairing any holes (subject to permission) b)Seal over the frame with board and use that as the outer leaf. i'm not really keen on either!

Not either but both. Option A alone does not give you a soundproof wall, the cladding is to thin to soundproof against much except normal talking. Option B gives you a single soundproof leaf but if you don't also do option A, then your newly boarded wall will get wet, grow mushrooms and fall apart.......unless you use marine ply (expensive), even then your cladding + existing outer framing will get sogy and fall apart.

[quote="rmproduction"]Just had another thought - What if i used a plastic wrap as per my first thoughts (as a vaour barrier not retarder) and then install dehumidifiers in the air gap between outer and inner walls (maybe loads of silica beads as well? so rather than let the moisture excape i let it get absorbed by these? Silica can only absorb so much before it needs drying out again. Dehumidifiers are not necessary in a void if you have adequate ventilation/ mechanical extraction. They also create noise and if one breaks down you will have to get into the wall to replace it. The more I type the crazier this idea sounds! I've been reading non stop on vapour barriers/retarders and realise the importance of not letting moisture build up. If i also used the insluation i've read about that is mold/rot resistant - would this idea not be as effective? (maybe moreso as moisture is eliminated from the area rather than just left to make its way out>? [The insulation may be mold/rot resistant but the timber it sits between sure isn't, you will be left with a pile of crumbly timbers but at least will be able to re-use the insulation for the rebuild :lol: I was also thinking whether or not there was any material that would prevent water entering through the cladding AND be breathable? Yep, the tyvek/breathable felt does this. It sits on a roof under your tiles and prevents any leaks or drips from getting in, but lets the water vapour out. Like goretex for buildings (if you're familiar with goretex, try wikipedia) So if any of this would work - i could wrap the plastic/material around the wood frame + cladding - reinforce the wall with plasterboard between the frame (so cladding plastic plasterboard = 1 leaf) then fill the frame with the resistant insulation?? Another thought that occured was whther it would be possible to fit tyvek or another similar material to the cladding from the inside? (i've searched the tyvek site but cant find any information on this) Tyvek on this inside of the framing is a bit of a bodge. The way I see it is this. The exterior cladding is designed* to be used against the elements. It's supposed to get wet and be battered by wind and sun all day long. The timber framing is not. You have already mentioned that there are holes in the cladding, this is your first problem. Before thinking about studio walls/ soundproofing/ what colour to paint the drum booth, you need to make the building watertight and weatherproof. This would be MY first priority. *Assuming it's properly installed and maintained.

rmproduction wrote:

Deluks did you manage to check out my other thread? Bottom walls have brick on the inside - leads me to believe that that is a double leaf wall already and watertight. Ive attached the picture showing both a bit of the upstairs framing and the downstairs brick. I see a lot of problems arising with this build - i know the guys on this forum will be a great source of support and inspiration and constructual criticism! Cheers

A brick wall and a timber clad exterior wall may be double leaf in building terms, but for a soundproof studio I would just treat this a single leaf, or increase the mass of either of those considerably. Is the cladding knackered on the downstairs wall too? Have you checked the brick wall for damp? If any moisture can get behind cladding and onto a single thickness brick wall then this will almost definitely create damp problems.