Garage conversion - wall insulation, boiler and gas pipe questions

[JonHeath]

Hi all,

I'm doing a garage conversion. The external walls are solid brick (9" thick). My building control officer has pointed me towards a calculator to make sure I get the right PIR insulation thickness to hit a 0.3 U value rating. This came out as 50mm on the celotex calculator. This includes a "low emissivity 25mm cavity" with "timber 25 x 47mm counter battens at 600mm intervals". I also have pipework and a boiler on this external wall. I mentioned this to the Building Control Officer and he wanted me to protect the gas pipes with some sort of steel shielding. So I have a bunch of questions if people don't mind:

1. First one is on installation of the PIR insulation. I'm assuming it is basically saying that I should set out studding on the brickwork at 600mm intervals. I then fix the PIR insulation to this studwork, leaving a 25mm cavity behind it. I then butt together the PIR sheets, mechanically fix them, and I believe I then tape them?

2. How does the plasterboard then go on top of the PIR insulation? just mechanically fix them through the insulation to the same underlying battens? (I know you can get the PIR celotex sheets with plasterboard stuck on but they seem very expensive)

3. What sort of steel protection do I need to give the gas pipes? Can someone point me to a product please? These would be in the

4. The boiler / vent pipe is installed on the brickwork at the moment. I understand this is OK, but I'm trying to picture what people normally do in this circumstance. Build boxing around it and PIR insulate the boxing was one idea I had? I'd have a cupboard door on the front with PIR insulation on the back of the door. Sound alright, or other ideas?

Thanks

 

[noseall]

1. First one is on installation of the PIR insulation. I'm assuming it is basically saying that I should set out studding on the brickwork at 600mm intervals. I then fix the PIR insulation to this studwork, leaving a 25mm cavity behind it. I then butt together the PIR sheets, mechanically fix them, and I believe I then tape them?

Either fix 25mm x 50mm battens to the wall, then fix your insulation sheets to this. Or place the insulation sheets against the wall (they can be blob fixed with adhesive as a temp' stay) and trap the sheets directly to the wall by fixing the same batten through the sheets.

Both methods - the insulation joints should be foil taped.
Both methods - the boards are fixed to the same batten.

We usually batten the wall first. We fix a lateral batten top and bottom (usually 100 x 25mm) and then skew screw the uprights to these and supplement fix say another three times along the length. You are best bonding or offsetting the insulation joints so that they don't clash with plasterboard joints and the insulation joints don't necessarily need to land on an upright batten. However, the plasterboard joints do.

 

[noseall]

2. How does the plasterboard then go on top of the PIR insulation? just mechanically fix them through the insulation to the same underlying battens? (I know you can get the PIR celotex sheets with plasterboard stuck on but they seem very expensive)

We always fix separates for the previous post reasons. Insulated plasterboards are notorious for hairline cracking on the upright joints. With separates, you can stagger the joints.

 

[noseall]

3. What sort of steel protection do I need to give the gas pipes? Can someone point me to a product please? These would be in the

4. The boiler / vent pipe is installed on the brickwork at the moment. I understand this is OK, but I'm trying to picture what people normally do in this circumstance. Build boxing around it and PIR insulate the boxing was one idea I had? I'd have a cupboard door on the front with PIR insulation on the back of the door. Sound alright, or other ideas?

Thanks

Any trapped gas pipes should be protected with tape then surrounded in plaster.

Ideally, the boiler should be mounted onto the skimmed plasterboards or brought forward if it is currently fixed directly to the masonry.

 

[noseall]

Hi all,

I'm doing a garage conversion.

Try and do as much of the bulky internal work as possible, before bricking up the garage opening.

 

[freddiemercurystwin]

I believe there should be a batten either side of the gas pipe to minimise gas leaking all the way through the building if you do get a leak and then a steel plate over the front of the battens to protect it, then mark the floor to indicate there's a hidden gas pipe. Though obviously once carpet is down that's lost, same with tiling or whatever. I'm not sure they are the official regs but that's what BC have asked for in the past.