Hi all,
At the moment I have a 40 year old prefabricated detached garage at the back of my house. It's falling apart and is generally in a poor state of repair, so I'm planning on removing the old building and constructing a new building in its place. I'm no bricky, but I'm reasonably handy with a good eye for details so I am going to build a timber studwork replacement.
I was just hoping you could sanity check my design, and answer a few specific questions around points that I'm uncertain on. Please keep in mind that I'm trying to keep the price down where possible, so cost is a consideration in my choice of materials and methods.
As it is just an outbuilding, I'm not too concerned about thermal performance, however I would like to make sure I tick the right boxes as far as weather-proofing and condensation prevention are concerned. Additionally I'll be adding a bit of insulation so that it is tolerable to work in when temperatures are extreme.
Once I've taken down the existing garage, I will have a 4.6m square concrete slab to build off of. So I'm planning on using 2x4 timber studs to build the wall frames and 11mm treated feather board for cladding. I'll board the exterior of the frame and roof with plywood sheets, and then the external roof will be coraline corrugated roofing panels.
The frame wall and ceiling joist cavities will be filled with insulation (I'm thinking maybe 75mm polystyrene sheets cut to fit the gaps between the stud members) followed by an inner wall of plywood again.
So in a nutshell, is that sensible?
With regards to specific questions, I have a few:
Thanks in advance.
At the moment I have a 40 year old prefabricated detached garage at the back of my house. It's falling apart and is generally in a poor state of repair, so I'm planning on removing the old building and constructing a new building in its place. I'm no bricky, but I'm reasonably handy with a good eye for details so I am going to build a timber studwork replacement.
I was just hoping you could sanity check my design, and answer a few specific questions around points that I'm uncertain on. Please keep in mind that I'm trying to keep the price down where possible, so cost is a consideration in my choice of materials and methods.
As it is just an outbuilding, I'm not too concerned about thermal performance, however I would like to make sure I tick the right boxes as far as weather-proofing and condensation prevention are concerned. Additionally I'll be adding a bit of insulation so that it is tolerable to work in when temperatures are extreme.
Once I've taken down the existing garage, I will have a 4.6m square concrete slab to build off of. So I'm planning on using 2x4 timber studs to build the wall frames and 11mm treated feather board for cladding. I'll board the exterior of the frame and roof with plywood sheets, and then the external roof will be coraline corrugated roofing panels.
The frame wall and ceiling joist cavities will be filled with insulation (I'm thinking maybe 75mm polystyrene sheets cut to fit the gaps between the stud members) followed by an inner wall of plywood again.
So in a nutshell, is that sensible?
With regards to specific questions, I have a few:
- 1. How do you suggest I fix the bottom of the stud walls to the concrete slab? It seems like using a powder actuated tool to fix a treated 'sole plate' to which I can attach the base of the wall is the best way, but are their simpler or more cost effective alternatives? As I don’t have a powder actuated tool, could I simply drill into the slab and install bolts that I can then bolt the sole plate to?
2. Bearing in mind that I have no history of the slab construction, do I need a dpc? I've seen rolls of 100mm wide dpc sheets... would I just run this under the sole plate?
3. Regarding membranes and vapour barriers, I think I need to add a vapour barrier between the external plywood boards and the cladding/roofing. Is that right? Do I need it anywhere else such as under the interior plywood boards?
4. How do I fix the external vapour membrane to the plywood board? Can I just staple it to the board, or do I need to create a gap using battens? Which side of the battens would the membrane go?
Thanks in advance.