Outbuilding conversion - Insulation

[BAGGIES1]

Hi,

I am currently musing over converting my outbuilding into a kitchen.
The current outbuilding is about 10m long and about 2 meters wide.

The outbuilding is combined into 3 rooms ending in an outdoor privvy.
I want to knock through he first 2 walls and leave the privvy to its own devices. The walls do not support the roof (which if aspestos cement sheet - but i would felt this and keep the roof as is) and contain no supporting electrics.

Basically my question is this. I want to create interior partition again the exisitng outer walls and a false level roof (the roof is slanted at 45deg) using 2x4 and plasterboard. A lot of folks have recommend using jabalite or insulation slabs as insulation but i recently converted my garage into a soundprrofed studio using 2x4, platerboard and 170mm rockwool insulation. Because the walls may be slightly uneven I feel the job would be better servered by rockwool for insulation.
What do you think?

I also understand that planning regs may be required to knock down interior walls. Can anyone give any guidance on that issue?

Any help would be great thx.

 

[^woody^]

If you are going to do this right, then it will need to conform to building regs and so it may not be so straight forward.

You don't need planning permission for demolishing interior walls, and building regs approval is only needed if they are structural - ie supporting something.

I am curious how you got 170mm insulation to fit in between 4 x 2 timber - did you compress it or build the wall out? If you want to do this on an external wall, then you should fit a vapour-check layer and also a breathable membrane before the external brickwork. But current regs will require something better than rockwool unless you build a really thick timber wall.

In addition you should consider the extra loading of the ceiling onto the external walls and insulating and ventilating the roof void to prevent condensation.

 

[BAGGIES1]

I am curious how you got 170mm insulation to fit in between 4 x 2 timber

yes i did compress it in the orginal project as it was for soundproofing

If you want to do this on an external wall, then you should fit a vapour-check layer and also a breathable membrane

ok there you got me....would the damp proof membrane i have used on the floor (before concreting over) be used on the walls for that purpose? vapor-check layor? could you expand on that a little for me

But current regs will require something better than rockwool unless you build a really thick timber wall.

ok. the wall will be 4 inch thick essentially. I assume it would have to be thicker than that if i wanted to use rockwool. What do you suggest (or plan regs suggest) as the best insulation material to use?

any feedback wud be great thx

 

[^woody^]

A vapour check can be either foil backed plasterboard, or polyphene as used for DPM. The idea is to stop moisture from the room from getting into the timber frame. The breathable membrane stops moisture coming in to the timber frame, and also lets it breathe.

Rockwool on its own would be impractical to insulate to current building regs. Without doing a calculation, it would probably need to be over 250mm thick. Compressing rockwool will cause it to be less efficient

An insulation board such as Celotex ot Kingspan (not polystyrene) would be needed both in between the timber studs and accross the internal face or in the cavity, probably something like 100mm and 50mm respectively.

 

[BAGGIES1]

right i'm a little out of my depth here.

but...as i understand it....

the thermal plasterboard (foil backed) protects the wood from the inside of kitchen....."vapour check"

a DPM - that bit lost me.....another material that sits between wall and 2x4??

whats protects the wood/insulating material from the wall?


ok ...insulation material...

An insulation board such as Celotex ot Kingspan

ok good so far...

would be needed both in between the timber studs

between the wood partition frame...ok

and accross the internal face or in the cavity

er? bit lost now...i'm thinking there's only the space inbetween the wood, plasterboard and wall. i'm missing something...


what do you mean? sorry if i sound a bit out of depth ^.woody^

just trying to put the mental picture together...

 

[^woody^]

I think we are talking about different things.

You're original post mentioned using 4 x 2 and plasterboard. This suggested to me that you had built a new timber framed internal leaf, and wanted to do something similar.

But it seems from your other thread, that you are thinking of ' Dry Lining ' ie fixing some battens to a wall and then plasterboarding.

These are two different things, so you need to determine what you want to achieve.

Dry lining is a cheap and cheeful way to get smooth walls in a porch or store or garage. It will not give you much thermal or sound comfort, and on its own is not sufficient for a room or kitchen conversion.

Rather than try to explain, if you search google, you will find lots of images of a dry lined wall and a timber framed wall. You need to decided what specification you want to go for - something cheap and thermally inefficient, or something better and to todays building regualtions.

The condition and thickness of the existing wall is a consideration too.

Also, you may like to keep to a single thread about this as this will get you better answers as the thread develops

 

[BAGGIES1]

ok. thx for your comeback.

i'm feeling after looking at google, that the timber framed option , while obviously the best, will probably be beyond my skills, knowledge and budget. plus the outbuilding is only 2m across therefore making space a premium. my first assumption being that the timber frame option will use up more space?

dry-lined:
probably not to bothered about sound issues as outbuilding leads to 150ft garden in quiet area. (assume thats what you meant accoustically)

thermally it would be nice to achieve some success however the outbuilding/kitchen is and probably will continue to be seperated from the house via double glazed door so at least it wont take away from the general warmth of the house hopefully if i choose that option.

so given that, the only thought in my mind is.... even with dry-lined i will need a DPM between the brick and insulating material/wood?? is this a sheet of plastic, is it special material i can buy?

again please bare with my lack of knowledge, i do have reference guides but my information i require is a little more specific. (or at least talking to you good people gives me more re-assurance about the job)

thx.

 

[BAGGIES1]

okay ignoring my previous post the timber frame would actually be smaller in size than what i had planned.

couple of questions on timber frame if i may.. (as ever)

i have a concrete floor...can i secure the wall frame to the brick wall with anything at all? metals brackets? how do i get behind to secure them once the partition is complete? if not do i try to secure into the concrete floor and to the ceiling ? (sounds iffy than one)

where will my electrical wiring sit? assumedly inside the partition somewhere?

any ideas on how thick Celotex or Kingspan i should aim for? 50, 75, 100mm?

which type is generally cheaper? would you buy of ebay?

the design i've seen on the net suggests a sheeting board on the other side of the partition (with the breather membrane attached, ie the wall side). is this an acceptable, lighter and cheaper option than another length of plasterboard?

got headache now...

as ever help is always appreciated...

thx