Plaster board with insulation how to fix it?

David_Aldred

Dear Anna,
Your first posting hinted at your concern regarding warm moist air getting behind the system and condensing out. You also had concerns over the adhesive and somebody posted dry wall adhesive will be fine.

Anna you are absolutely right with your gut feelings there is a very real danger of warm moist air getting behind the system and if it does it will be on the cold side of the insulation and trickle down the inside of the system until it comes out soewhere.

If this point at where the moisture trickles out has wood adjacent to it the wood will be at risk of consequential decay. In addition standard dry wall adhesive is very hygroscopic (that is it attracts moisture from the air like mad) and British Gypsum who manufacture it strongly recommend it is not used in a damp environment.

There are other grades of dry wall adhesive which are waterproof that can be used so just make sure which type is being used.

Insulated dry lining systems to damp solid walls have to have a fully effective vapour barrier to prvent warm moist air from in this case the kitchen getting behind the system and condensing out. In addition some people also vent externally on the cold side of the system to remove any moisture laden air acumulating there that may otherwise become a saturated environment.

Out of preferance we would like to see a polyethylene studded membrane applied to the wall first (see Delta or Oldroyd or other similar products) then the insulation system complete with effective vapour barrier. Also remember to remove all timber including wedges etc buried within the wall you are applying th esystem to and be mindful of penetrating the system with services etc which must all be sealed if you do.

Kindest regards David Aldred Independent damp and timber surveyor

TCC_2

Just general advice on buildings.

People think about damp and plastered walls the wrong way. Think of buildings this way. Walls beathe! The best cure for dampness in a wall is to cure the cause and then letting air get at the wall so any moisture will escape out into the room.

I'm not saying that is the case here, just giving general advice.

Example: Couple have damp in exterior wall so seek to render exterior wall, or apply paint or other coverings, to 'waterproof' it. This will MAKE THE PROBLEM WORSE as it will then seal in any moisture and effectively stop the wall/surface beatheing.

The best cure for dampness is air circulation and letting the wall beathe.

There are 3 causes of dampness in a building:


1: Penetration. Broken drainpipes or gutters or leaky pipes such like. Generally, anything that physically allows water directly onto the walls .


2: Physically: Such as a faulty, or a 'bridged', DPC [Damp proof Course]. This allows damp directly into the bricks in the wall and can be along the footings/bottom of the walls, or where exterior [garden] walls abut the house walls, or at window/door frames. The 'bridging' of a 'cavity' also in this section... the cavity seperates the exterior 'wet' course of brick from the 'dry' inner course... if you physically bridge or join them [such as with dropped mortar] it allows damp to enter the inner wall. This is why you have a cavity.


3: Condensation: steam from a kettle or moist air in a bathroom. The cure for this is to air the room, i.e, opening a window or fitting air-bricks or vents.


The above is a quick quide to the basics. If you have damp, open a window every chance you get.

anna.bloom >"Building regs have said we need 5cm! of that expensive foam type insulation with a stud wall. No way, we wont have a kitchen left! 10cms would take too much out of the room."


You'll find the BRs specify a value of insulation needed and that they say 5cm of that particular type of insulation will suffice.

Just FYI, there are other type of insulation [i.e foil backed plasterboard] that won't intrude into the room so much.