Single brick extension

120624

The house we own (ex council) has a single brick building at the rear that was used for a toilet and storage, it was then connected to the building at a later date. It has electric throughout and water supply.

I am thinking of knocking down the interior walls/doors and turning this space into a utility room and moving the toilet further back into the building (area that says shed) and possibly fitting a shower/wet room if space allows.

My idea was to insulate and plaster over the single brick but I’m not sure if that is following building rules or might affect when we intend to resell. Can anyone give any advise? I’ve included current drawing of building and image of what it looks like.

Based on below pics would it be worth just knocking down and starting again?!

 

grumbler

I think it's double brick (without a cavity), not single.

With such small space inside it's worth considering external insulation.

ka7e

We did something similar last year - 2 storerooms and an outside loo knocked through to make an inside wetroom. The builder used insulation like padded foil and plasterboarded over. With a zoned electric heater (suitable for bathrooms) it's quite warm. Moving the toilet and associated drainage might need building regs and incorporating a shower will mean it's designated as a bathroom which brings a lot of restrictions regarding electrics etc.

TELLIT01

grumbler said:

I think it's double brick (without a cavity), not single.

With such small space inside it's worth considering external insulation.

Compare the external measurement to the internal to determine whether it is single or double brick.  Our house has a similar section and it is definitely single brick.

FreeBear

grumbler said: I think it's double brick (without a cavity), not single.

With such small space inside it's worth considering external insulation.

Would lose 75-100mm per wall insulating internally, and the ceiling would also need to be done. Would be as well to dig out the floor and insulate that too. External insulation may be an option if there is enough overhang on the roof, but the felt looks like it could do with being redone and some lead flashing fitted.

Certainly looks like a double thickness brick wall - Should measure around 215mm thick. If it were a single skin brick, there wouldn't be an internal cill in the toilet.

stuart45

It's the brick bond, Flemish Stretcher bond, that suggests it's probably a 9 inch wall.

Jeepers_Creepers

Looks in good order, and fits in with the rest of the house.

The roof looks as though it could do with recovering - that's poorly-applied felt, and it would give the whole thing a major lift having proper fascias and stuff anyway. Allow a nice overhang all around, and even consider making the front one significant - 2' or more to make it a feature, provide shelter, fit downlights - stuff like that. Give it all some thought before starting. Though no harm in keeping it essentially as it is.

There's already a loo and utility stuff in there, so personally I wouldn't entertain Building Regs as this would almost certainly impose far too much obligation on insulation and things like that - it'll cost, and also reduce the internal space a significant amount.

All you'll be doing visibly is recovering the roof, and (hopefully...) replacing that end door with a window?

Are you DIYing?

This is what I'd do; remove the floor covering and see if there's any room to add insulation down there. If so, fit what's easy to fit - if it's only 2", that's plenty. Simplest way: DPM, sand screed to provide a perfect level, 2" rigid insulation sheet, 18mm chipboard flooring floated, with T&Gs glued. Jobbie jobbed.

Walls: tanking slurry tobesure tobesure, and bond on 2" insulated plasterboard. (This should also have the odd mechanical fixing too, but in this case I wouldn't bother. I'd remove all the internal walls first (that you were going to do) and then slurry and board the whole walls. Build your studs walls afterwards, bonding/adhering the stud to the new wall - no screws going through.

Ceiling - ditto. Depends what's already there.

Do this, and it'll be the warmest and easiest room in your house to heat.

When it comes to sell (when will this be?) it'll be seen by all buyers as an asset. If they question BuildRegs, you tell them it was used as a utility room and loo for yonks (keep the old photos...), and they wouldn't be asking about BRegs if it was still like that. What you have done is significantly improve its insulation value and quality, and they will see and feel that it is a comfy addition. The lack of BRegs is a problem for them? Go look elsewhere. 

Obviously, of course, do the important things properly - good extraction in the shower room, opening - to vent at least - windows, etc.

I'm not suggesting this is what you should do - it's just what I would do. Or else it's going to become costly and 'silly'.

FreeBear

Jeepers_Creepers said: Walls: tanking slurry tobesure tobesure, and bond on 2" insulated plasterboard. (This should also have the odd mechanical fixing too, but in this case I wouldn't bother. I'd remove all the internal walls first (that you were going to do) and then slurry and board the whole walls. Build your studs walls afterwards, bonding/adhering the stud to the new wall - no screws going through.

No, no, and no. Tanking the walls is totally unnecessary and could cause problems in the future.

Yes, insulate the walls internally, but use the warm batten method. This leaves a 25mm void between the insulation and the brickwork which will allow any moisture to dissipate as long as there is a bit of ventilation. Using foil faced insulation boards avoids the need to use a vapour control membrane as long as the joints are taped. It is also reversible should the insulation ever need to be removed.

Likewise for the floor - If the existing surface is low enough and the OP doesn't want to dig it out, lay insulation boards topped with chipboard or ply and have a fully floating floor. No need to mess around with screed.

Jeepers_Creepers

FreeBear said:

Jeepers_Creepers said: Walls: tanking slurry tobesure tobesure, and bond on 2" insulated plasterboard. (This should also have the odd mechanical fixing too, but in this case I wouldn't bother. I'd remove all the internal walls first (that you were going to do) and then slurry and board the whole walls. Build your studs walls afterwards, bonding/adhering the stud to the new wall - no screws going through.

No, no, and no. Tanking the walls is totally unnecessary and could cause problems in the future.

Yes, insulate the walls internally, but use the warm batten method. This leaves a 25mm void between the insulation and the brickwork which will allow any moisture to dissipate as long as there is a bit of ventilation. Using foil faced insulation boards avoids the need to use a vapour control membrane as long as the joints are taped. It is also reversible should the insulation ever need to be removed.

Likewise for the floor - If the existing surface is low enough and the OP doesn't want to dig it out, lay insulation boards topped with chipboard or ply and have a fully floating floor. No need to mess around with screed.

It's a modernish build - almost certainly has a DPC. Damp will be minimal, but this ensures that none will get trapped behind the insulated boards. It's a belt and braces approach (no, I wouldn't suggest it for a traditional stone wall or similar.)

And if you are going to batten, then you will be driving dozens of screws into that wall. A vented void? How? Vented to what?

And by 'screed', I mean the thinnest layer of sand just to get the floor level and to protect the DPM, that's all, so any rigid insulation board has a nice flat surface to lie on.

grumbler

Jeepers_Creepers said:

FreeBear said:

Jeepers_Creepers said: Walls: tanking slurry tobesure tobesure, and bond on 2" insulated plasterboard. (This should also have the odd mechanical fixing too, but in this case I wouldn't bother. I'd remove all the internal walls first (that you were going to do) and then slurry and board the whole walls. Build your studs walls afterwards, bonding/adhering the stud to the new wall - no screws going through.

No, no, and no. Tanking the walls is totally unnecessary and could cause problems in the future.

Yes, insulate the walls internally, but use the warm batten method. This leaves a 25mm void between the insulation and the brickwork which will allow any moisture to dissipate as long as there is a bit of ventilation. Using foil faced insulation boards avoids the need to use a vapour control membrane as long as the joints are taped. It is also reversible should the insulation ever need to be removed.

Likewise for the floor - If the existing surface is low enough and the OP doesn't want to dig it out, lay insulation boards topped with chipboard or ply and have a fully floating floor. No need to mess around with screed.

It's a modernish build - almost certainly has a DPC.

How modernish can be an outdoors toilet and what sort of DPC? I don't see any blue bricks.

FreeBear

grumbler said:

Jeepers_Creepers said: It's a modernish build - almost certainly has a DPC.

How modernish can be an outdoors toilet and what sort of DPC? I don't see any blue bricks.

I would take a stab at it being a 1920s or 1930s build. The main house will have a DPC (probably a poured bitumastic layer), but without a closer look, the extension may not. If there is one, it could be buried below the level of the path.

Jeepers_Creepers said: And if you are going to batten, then you will be driving dozens of screws into that wall. A vented void? How? Vented to what?

Vertical battens on 600mm centres with 5-6 screws each. A 10mm weep hole every 1.2m along the base and again at the top - Doesn't need much.