Partitioning Garage

[PolarNorth78]

Good Morning,

I have an integral garage which is double skin contruction where part of the main house (about 1500 mm) and then single skin with piers for the protrusion. The upstairs wall is supported by a concrete lintel. The floor is concrete and stepped down from the main house.

I am thinking of placing a stud wall underneath the lintel to create a cloak room and put a washing machine and dryer in there. The main drainage stack is in the corner.

My outline thinking for the stud wall is a twin stud on top of block with a damp course to create a cavity for a sliding door (saves space), studs filled with celotex/kingspan, overboarded on the house side (if needed) and the plaster board. The garage side will have fireproof board. Of course this hinges on getting a sliding fireproof door (no pun intended).

The bathroom is above the would be cloak room, hence my desire to parition at the lintel as the garage is a massive cold sink.

In terms of this:

1) Do I need any form of building control sign off or similar?

2) The gas meter is in the would be cloak room/washing machine room. Does this have any impact on things?

3) Does the stud wall plan sound reasonable? Is there anything I need to consider?

4) Any hints and tips that would be useful?

Thanks in advance.

 

[noseall]

1) Do I need any form of building control sign off or similar?

Yes, BC approval. Needs an application.

2) The gas meter is in the would be cloak room/washing machine room. Does this have any impact on things?

There may be an argument for the fact that you are now building over a gas main (stud wall), but I find that a wee bit contentious seeing as the meter is already internal. Does the meter pass under the proposed stud wall or is it incoming direct from the outside?

3) Does the stud wall plan sound reasonable? Is there anything I need to consider?

It only needs be single skin stud. We do ours to a decent spec' i.e. (outside to in)....
12.5mm fire-line board (taped and skimmed).
12.5mm regular board with joints staggered.
50mm PIR foil sandwich.
100mm stud wall filled with 100mm PIR foil sandwich.
18mm ply.
12.5mm plasterboard (taped and skimmed).

4) Any hints and tips that would be useful?

Self closing fire door required between new habitable and tiny garage. You can either build the stud wall on some squat masonry or direct to the floor with DPC fixed to the underside - depending how you wish to finish the floor. Just remember to be savvy with the membrane detailing.

 

[^woody^]

A sliding door does not save space, the swing area is still required to use the sliding door. You will lose more space by creating a wall 2.5x as thick as it needs to be

A 30 minute pocket door can go in a 150mm thick wall, it does not need to be cavity, but there will be consideration for the insulation requirement.

Also with a cavity wall it may need the internal leaf to have the fire protection to protect from the cavity. It's all about the detailing.

Gas meter is not an issue.

 

[PolarNorth78]

Thanks both, if it would need a BC application I would be minded to convert the whole garage. How come only this partitioned area would need one as its not really habitable (2-3 square meters at most)?

The gas meter would pass underneath the proposed stud wall. I havent traced the gas pipe but the entire garage floor is concrete.

Logic behind sliding door was to save space and because there is a concrete lintel above (so wall thickness is a bit academic as it would be thick anyway) and the lintel means I would be bang on or under the 2.1M minimum ceiling height when you add in floor insulation.

If im converting the entire garage, it does highlight the following:

1) It double skin then goes to single skin with piers, how best to deal with this - build another cavity, stud wall or something different?

2) I have a looped electricy connection to next door and the electric meter - how is this dealt with/relocated?

3) I have a soil vent pipe, how should this be dealt with?