My first post here so please be kind :D
I have been watching this site for many years hoping that one day I would build my own studio. And that day has now arrived :yahoo: I will start a thread showing where I have got to and will post up a plan of the building in due course but for now I need some advice on skirting boards.
The construction of the studio is a stand alone, timber frame affair at the bottom of my garden. It will have oak cladding over a 25mm airgap on batons with a vapour barrier and 6mm of external grade ply. The roof will be slate over a 6mm external grade ply, vapour barrier, 25mm airgap, heavy roof felt and slates.
It is 4Mx3M with a pitched roof 4M high at the apex and 3M high at the eaves. I don't play guitar loud and won't track drums. But I want a reasonable level of sound attenuation. The internal construction I was going for is a resilient strip, walls and ceiling, into the Apex (i.e. not flat) and then two layers of gypsum plasterboard, maybe one layer will be high density sound board with something like green glue in between the layers.
At the corners, I understand that the plasterboarding must not touch but be heavily caulked and overlayed/staggered one layer to another.
I was going to fit special skirting boarding to the plasterboard that would allow the running of cables within the skirting but I realise that at the corners, won't the skirting need mitring and wouldn't that impede the flexibility of the walls; wouldn't it be like short circuiting the resilient strip?
Resilient channel/skirting board question.
Originally posted at johnlsayers.com, topic 15871.
welcome! on the skirt - yes mitre it for looks and just plan on leaving some gap which you can seal with caulk if you're concerned about any hard contact but if you're not looking for a high isolation structure then the contact shouldn't be a problem.
Okay, will do, many thanks Glenn:D
The vapor barrier, if it needs to be in the build @ all, based on climate, should be on the interior side of the wall.
Is that what you are saying? It reads like you will have this barrier more in the middle of the assembly if not on the external side of the wall assembly.
Whatever is typical for your climate is what you should do, and that should be based on standard construction from professional builders...not what a friend of a friend says ;)
X Space, the type of VB I am using is designed specifically for timber frame construction and is certified as such:
http://www.webdynamics.co.uk/images/09% ... 0walls.pdf
It is certified by UK Building Controls for use in between the timber frame construction and the outside barrier - in my case, a slate roof and oak cladding weatherboarding :wink: It allows the passage of air out but resists water drops coming in.
"6 Risk of condensation
6.1 The product has a design resistance to water vapour transmission of less than or equal to 0.6 MNsg–1 and is defined as a ‘breather membrane’ in accordance with BS 5250 : 2002. Therefore, it will contribute towards minimising the risk of interstitial condensation in suitably designed walls (see section 14, Table for Physical properties — general).
6.2 The risk of condensation occurring within the wall of a timber-frame building will depend upon the properties and vapour resistance of other materials used in the construction, the internal and external conditions and the effectiveness of the internal vapour control layer"
Exactly, this is not a vapor barrier as I was trying to say. It is "house wrap" which is designed to protect the wood sheathing from wind driven moisture. It is a standard building practice. This is another product, same function, different side of the ocean : http://www2.dupont.com/Tyvek/en_US/index.html
A vapor barrier, more correctly called a vapor diffuser retarder (VDR) in >most< cold to moderate climates will be a solid sheet of poly installed directly on the interior side of the final framed wall and then covered with the interior sheathing.
The wall assembly, as mentioned above the except from the document you posted, the materials used, etc. will determine if a vdr is required at all.
Okay, so if I am using (from the inside-out) one layer 15mm plasterboard, green glue, 15mm foil backed plasterboard, resilient strip (walls); resilient bar and isolation clips (ceiling); 4x2 stud wall with 4" Rockwool insulation; 6mm external grade plywood, VB; 25mm air-gap (battens) oak cladding (walls) and 5x2 roof joists; 4" Rockwool insulation, 25mm air-gap; 6mm external grade ply; VP; 25mm air-gap (battens); heavy duty roof felt; 25mm air-gap (counter battens) and roofing slates, where would you ideally situate the poly in those layers?
I am guessing in between the ply sheeting and the studs/joists?
Are we talking about the house wrap or the actual vapor barrier?
Interesting subject of VCL and breathable membranes. Some internet research shows a lot of conflicting research outcomes which casts doubts on whether VCL is required or not. Seems the orginal 1938 research in the USA may have been flawed and that diffused moisture through a building wall construction is not the prime cause of condensation build up.
However, what the standard practice seems to be is that a VCL is fixed over the wall studs in between the resilient strip and the first layer of plasterboard - is my understanding correct?
The VCL (poly)Are we talking about the house wrap or the actual vapor barrier?
It reads like you are making this up:) A VDR...(what is a VCL?) formerly known as a vapor barrier has only one place to go. In the consideration that vapor moves from the warm side to the cold side then it is with no regret that we establish this barrier on the inner most side, rather than trap this potential moisture trap/mold producer in between the sheathing of a wall assembly. This applies to a cold environment. In your research in what exactly a vapor barrier is and to what it might address, you most likely have come across the initial condensation issue that is common to cold climates. You may have spent a few minutes in addressing the wind and how the air and water laden flakes and the driving wind can deteriorate a wall. But I can only assume this is where you are going. One of the main issues with how a building is able to mitigate condensation build up is via a properly fitted HVAC extraction unit. "Seems the orginal 1938 research in the USA may have been flawed and that diffused moisture through a building wall construction is not the prime cause of condensation build up." I do not even know what this means:) The data comes from the Northern regions, not specifically the U.S. but the cold areas in general, the cold climate...the place where vapor will move and "condense" on the building assembly and eventually rot it. So, to answer your question, the poly goes directly on the interior of the final framed assembly....IF it needs to be there at all. You should ask someone local if you are having doubts...Interesting subject of VCL and breathable membranes. Some internet research shows a lot of conflicting research outcomes which casts doubts on whether VCL is required or not. Seems the orginal 1938 research in the USA may have been flawed and that diffused moisture through a building wall construction is not the prime cause of condensation build up. However, what the standard practice seems to be is that a VCL is fixed over the wall studs in between the resilient strip and the first layer of plasterboard - is my understanding correct?
I'm really not making this up - VCL = Vapour Control Layer which is what it is known as in the UK.
1938 research :http://www.housebuildersupdate.co.uk/2007/07/little-known-history-of-vapour-barrier.html
My building is a 4x3 M standalone construction that is not subject to Building regs control as it falls under "permitted Development" laws so I am free to do whatever I like to it in terms of construction. But I want to do the "right" thing here - so to fit or not fit a VCL on the inside stud wall sandwiched in between the resilient strip and the stud wall is the question I'm asking myself at this time. BS 5250 is the British Standard for Condensation in buildings. This is what it recommends:
7.1.3 Controlling interstitial condensation
To minimize interstitial condensation, it is necessary to do one or more of the following:
a) obtain low vapour pressures by ventilation, and/or reduced moisture input to the building;
b) use materials of high vapour resistance near to the warmer side of the construction;
c) use material of low vapour resistance, or provide ventilated cavities, near the colder side of the
construction;
d) use materials of low thermal resistance near to the warmer side of the construction;
e) use materials of high thermal resistance near to the colder side of the construction.
NOTE Any one particular procedure taken in isolation might not necessarily minimize the risk of condensation.
http://www.commercialconnections.co.uk/ ... ldings.pdf
If I understand correctly, the VCL should be contigeous over the stud wall to seal the room space to prevent moisture dispersing to the outside building layer and condensating in the building materials. However, If that is done, then the moisture has to go somewhere - so I see where you are coming from in terms of ventilation and HVAC to combat condensation. The usual way according to UK building regs is to allow plenty of ventilation to lower vapour pressure; I guess its a balance of thermal efficiency vs condensation/mould build up? For a studio, ventilation is a problem becasue of sound so I guess I need to do more research.
It will have 24/7 electric heating, thermostatically controlled (unless we get a power failure :evil: ) so the inside temp will always be at least 21deg C, 72deg F or higher in Summer but only few days per year. The studio will only be used as a studio a few hours each week so for the most part, ventilation is no problem - there are two small windows with louvres to open. And when I do record and need to close everything down, would that be a real problem in terms of causing condensation build up?
So given all the above, if this were your studio, what would you recommend? I'm really grateful for the advice - this is a minefield without any seemingly hard and fast rules.
Talking to local builders, they say "it depends." Depends on how you use it, how you heat it, how you ventilate it, how you insulate it, what materials you use etc., etc..........
I'm thinking of not putting in a VCL but installing a a Daikin A/C.
http://www.daikin.com/global_ac/product ... ideos.html
Thoughts anyone?
This is my point. You refer to the VCL, a vapor control layer, as a Vapor barrier you did that in the first post. These are not only two(2) different things but have two(2) different functions.
A vapor control layer, based on the document you presented, will tell you we are talking about a >breathable> fabric.
If air can move then so can moisture/vapor...that applies directly to the >breathable< aspect. The goal is to make a wall assembly that can "breath" from the out side as well as from the inside, example gratis, the vapor can pass through the materials of the wall assembly from the out side to the inside and from the inside to the outside.
For anyone to suggest that the placement of either one, a vapor control layer OR a vapor barrier DEPENDS...only shows that you are talking to the wrong people:)
The VCL, a breathable and moisture resistant material, will go on the out side of the structurally sheathing and the VB=vapor barrier NON breathable,will go directly to the interior side of the framing.
It is that simple. If anyone is telling you different, then they are in doubt and you need to move up another step on the food chain and approach the code administration...they will give you a better idea of why those other guys are not so well known in the office:)
the AC unit does not provide a means of exhausting the stale air. so you still need an exhaust vent to move the stale air out and it should be matched to the air flow rate inbound. so you should also check the fresh air supply rate to determine if it is suitable.
xSpace, you have taught me lots here, and one of the key points is that there is a difference between a VCL and a Breathable Membrane. Apparently, the reason I was confused is that even builders use the phrase Vapour Barrier in the wrong context.
So I get that my Breathable Membrane is the building wrap that you see in my picture above - I now know it is not a Vapour Control Barrier, at least not in the UK. And I also get that you are suggesting that I consider putting in a Vapour Control Layer on the warm side of the wall to prevent transmission of moisture from the inside out. I understand this is usually made from polyethylene.
According to my local building controls officer who I spoke to on this matter, he did say that whether or not to fit a VCL " depends" on the construction, the materials used and how the room/are being used, heated and ventilated. For example, in England, bathrooms and shower rooms in new houses have to have forced ventilation provided.
But I also consulted a Building surveyor who told me that in his opinion, if I used a foil backed plasterboard in the construction, this would be regarded as a VCL. So with my Breathable membrane wrap on the outside and my foil backed plasterboard on the inside, would this be a good design to commit to?
Foil is actually the only material that passes the test as a "vapor barrier", where as poly (clear plastic) is a runner up, so to speak.
It doesn't surprise me that the names, acronyms and what-have-you are different from where you are to where I am...but the physics works the same no matter where either of us are.
Breathable on the exterior and impermeable on the interior, in cold climates is a globally recognized wall assembly.
"even builders use the phrase Vapour Barrier in the wrong context."
Day after day over here as well ;)
That makes me feel much better then :wink: It now looks as though my best option is to use poly fixed to the inside of the stud wall because I only want to use two layers of soundboard with green glue sandwiched and I can't get foil backed s/board - only ordinary gyproc board foil backed. Thanks for spotting this and for the help - much appreciated. :D"even builders use the phrase Vapour Barrier in the wrong context." Day after day over here as well ;)