Outhouse Conversion

[paulfitz]

Hello,

Just signed up and have got a project in mind, and im just wondering what ita gonna take, what i could do myself andd what im gonna have to get the pro's in to do.

Right here goes... About 3 years ago we moved into a concrete built 1950's terrace. Attached to the kitchen is a single brick outhouse, which was originally used as an outside toilet, so there is foul waste and a water supply plumbed in to the outhouse already.

The owner before us extended this outhouse further - with the view of making a shower-room, but then they split-up and the project obviously stalled. The extension is made of breezeblock, but is at a lower height than the adjoining area (yeah i dunno why either???) There is also no water supply or waste outlet for the extended area.

The floor all-through these 2 rooms is concrete, and i am fairly sure there is a screed laid, however it is quite damp in there as the job is unfinished, and tbh prob needs starting again.

The original outhouse has a flat-roof made from concrete slabs - which are rapidly disintegrating!!! And the extension has a ply??? roof covered in felt.

I would like to re-install the toilet, and make a utility area for washing machine and tumble dryer in the original outhouse. In the extension I would like a shower-room (prob with a shower tray, not a wetroom).

My queries are...

1. Do I need to make the single brick area a double skin to have it classed under building regs as a "habitable abode" (that was the terminology used in the full structural survey)???

2. Do I have to get planning permission for this conversion??? I am unsure if the prev owner got planning permission for the extension, but is has been there for over 5 years now... would they turn round and tell me to pull it down???

3. Could I get rid of the flat roof, and make it slightly tilted (towards our garden) so that rain runs off???

4. AND FINALLY THE BIG ONE.... Ball park figure on all the structural, plumbing and electrical work for this???


I know its been a long one, so thanks for staying with me, if you have. Any help will be greatly appreciated.

Cheers, Paul

 

[noseall]

1. Do I need to make the single brick area a double skin to have it classed under building regs as a "habitable abode" (that was the terminology used in the full structural survey)???

You will need to ensure the walls meet a certain thermal value and you are right in thinking a single skin wall is nowhere near adequate. This may mean adding block walls to the inside, or lining the inside with a stud wall with both scenarios requiring insulation within.

2. Do I have to get planning permission for this conversion??? I am unsure if the prev owner got planning permission for the extension, but is has been there for over 5 years now... would they turn round and tell me to pull it down???

You may not need p.p. as you may have not exhausted your p.d. rights. However you will require building regulations.

3. Could I get rid of the flat roof, and make it slightly tilted (towards our garden) so that rain runs off???

Yes you could. This may be done as either a flat roof with firrings (diminishing strips) with an insulated warm deck or it may be in your interests to fit a pitched roof with 300mm fibreglass insulation at ceiling detail.

4. AND FINALLY THE BIG ONE.... Ball park figure on all the structural, plumbing and electrical work for this???

You haven't produced any measurements so i'm just going to say £8000.

You may be better off demolishing and starting from scratch.

 

[paulfitz]

Cheers for the answers noseall as you can prob tell from my laymans terms i havent got a clue when it comes to buildings and the technical stuff

The original single brick room has been studded with some insulation (that awful candy floss rockwool type insulation) but im still not overly convinced that it would be warm enough without a 2nd skin of brick even if it was fully studded and insulated??? However I will get several quotes in and see which each firm says would be the best option.

What concerns me most is the roof. Flat roof's just arent designed for britain!!! But the concrete slabs will be a pain in the ass to change, but they do need it as they are rotting inside - i noticed they became much worse after the january snow & frosts

I am actually toying with the ides of getting some solar panels on the roof, so that can power the leccy items such as washer, tumbler and shower in there. I'll have to look into grants available for solar energy tho, as I tbelieve they are still pretty damn expensive!!!

Once again cheers for the advice noseall.

 

[ajrobb]

I'm still not overly convinced that it would be warm enough without a 2nd skin of brick even if it was fully studded and insulated.

A second brick skin won't add much warmth. Studs and insulated plasterboard (e.g. Kingspan K18) with 60 mm of insulation would give a U value below the regulation 0.3 but those walls would have a low thermal mass. As long as you have an existing high mass wall or concrete floor, the thermal mass might be enough to stop you baking in the summer through any south or west facing windows.

 

[paulfitz]

A second brick skin won't add much warmth. Studs and insulated plasterboard (e.g. Kingspan K18) with 60 mm of insulation would give a U value below the regulation 0.3 but those walls would have a low thermal mass. As long as you have an existing high mass wall or concrete floor, the thermal mass might be enough to stop you baking in the summer through any south or west facing windows.

We do have a concrete floor, but i dont know what a high mass wall is???

Im i correct in thinking that the if we have the correct wall and ceiling insulation and it is fullly boarded, then we wouldnt need to add a 2nd skin of brick???

I hope so because its only quite narrow as it is, and I wouldnt want to lose any more width.

I think the outhouse is south-ish facing and the window would be in virtual direct sunlight in the morning/ early afternoon - i suppose this would be ok as i want to use it as a utlity/drying area so clothes would be toasty dry pretty quickly and there wouldnt be much damp in the shower room.



Thanks for all the advice so far guys... Im starting to understand a little more now. Just wanna have a good idea of what I want so the builders dont think they can take the ****/ or think im a divvy or summit

 

[Deluks]

If the wall is already studded out then simply fixing a better type of insulation between and over the studs, with a plasterboard finish should sort you out. (celotex/kingspan type are usually best performing)

Similar question just asked:

//www.diynot.com/forums/viewtopic.php?t=217568

 

[ajrobb]

but i dont know what a high mass wall is

I think you say the house is concrete. Either concrete or brick is going to be pretty heavy. If one of the walls in the extension is the original external wall, it should take a good amount of heat to warm up or cool down.

If the wall is already studded out then simply fixing a better type of insulation between and over the studs, with a plasterboard finish should sort you out. (celotex/kingspan type are usually best performing)

With a single outer skin, it might be better to leave the cavity between studs as open and ventilated to allow the walls to dry out after rain.

If you want to use the extension for drying laundry, I would consider a quiet, humidity controlled extractor fan. Look for 'brushless motor'. Also consider lining the laundry and shower walls and ceiling with moisture resistant plasterboard. A toilet and/or shower would need ventilation too.