Hi guys
I have a small porch on my house which consists of 3 uninsulated walls( i am assuming ) and a cast concrete roof. The rest of the house has been insulated but this porch remains like a freezer with very bad condensation.
I am planning to dry-line the porch and ceiling in the conventional way, ie spaced 2x1 battens with styrofoam insulation between then drywall over.
Firstly, do I put a plastic vapour barrier under the plasterboard.
Also is there any more efficent method or product I could use instead.
Bear in mind that I want to loose the minimum of space inside the porch.
Cheers
James

Hi Jet,

For decent insulation, I would come off the block/brick/roof, at leasts 75mm and stuff with Rokwool. line the block/brick/roof with a semi-permeable roofing membrane. Then the timber, then insulation and then the plasterboard.

S

Hi Jet,

Another point is if there is no heating in the porch then it will be prone to condensation and variable degree's of temperature change as Simon has said you will need to insulate the concrete roof

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Thanks for that. I have also been told that I can use a foam backed plasterboard that can be stuck onto the wall directly.
Does anyone have any information on this ??

Hi Jet,

The foam back I have seen is only about 25mm thick, you will need far greater insulation than that. I realise you don't want to loose space, but anything less than 75mm and you will still have a condensation problem.

S

I have a similar problem and came accross this http://www.mgcltd.co.uk/Products/Thermal_and_Acoustic_Insulation/SEMPATAP_THERMAL I haven't used ityet , but it looks good.

Would that be

Have you seen the rip-off price.

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Kingspan do ones, see
INSULATED DRY-LINING PLASTERBOARD FOR PLASTER DAB/ ADHESIVE BONDING and

INSULATED DRY-LINING PLASTERBOARD FOR MECHANICAL FIXING

Appears to be made up to 82.5mm but not sure who sells that. I was going for the exact same thing but couldn't but it easily find it. Anyway there are just as easy ideas. CWPlastering & others have made some excellent suggestions. Also hoisting 8 x 4 sheets of 82mm thick drywall/insulation board about would not be easy me thinks

Check my posts in the other sections, as I have be annoying the lads here about the same topic let me know if you can find my posts

I would avoid any non standard method until you get verification from the regulars on here as there is always someone trying to sell something

No way I would pay 145 quid for a 12m x 1, roll of 10mm thickness . The thermal resistance is 0.158m2 K/w whereas a 20mm kingspamn standard insulation has a thermal resistance is 0.9m2 K/w

Hi all,

I'm having this exact problem in my porch and it's driving me nuts.
So if I stick some of this board on the ceiling, does it need to be slanted, for the water to run off? Or will the droplets stop forming altogether?

Presumably I'll need to dry the room out somehow before doing this.

As an aside, would drilling a vent make any difference?

thanks in advance,
rb

Hi Bryn,

You will need a dehumidifier in there (keeping the doors and windows shut) When it has stopped sucking water, is the time to insulate (summer is good for this). Hopefully, if the room is well vented and insulated, you shouldn't have any drops of water. Double glazed units are a must tho', or you will be waisting your time.

S

Thanks Simon,

The room isn't insulated or vented, it's just a single-skin box room, added on to the house as an afterthought. I'll try the dehumidifier as a temp fix, so I guess I might have to keep it running til the summer before I can get insulating.

Plus the windows and door aren't double glazed, so that could be another expense! Will this be necessary even with the room insulated?

thanks again