Thermal plasterboard

[RatRibs73]

But doesn't a fridge stay cold actively? The only way an insulated room could cool itself when warm outside would be air con surely.

[The Natural Philosopher]

So was I.

It seems to be that water will run down the outside of it, but wind will not go through it, and moisture can, in time, percolate through it from inside the walls.

I.e. it ensures that there will be no build up of moisture inside the walls, whilst providing a showerproof coating.

My walls are

- 12x12 oak frame infilled with 7x3 studwork. On a double brick cavity wall with rockwool battens inside.

Then layers from the outside:-

Render over mesh, onto 1" battens (airgap behind the render, open at the base to allow any possible water ingress to drip out I suppose. Then building paper, then 12" waterproof ply. Then the studwork, with rockwool filled cavity to foil backed 12mm plasterboard laid over the softwood studs and TO the oak frame.

In an ideal life I'd have used celotex for even better insulation.

This construction entirely satisfied 2000 building regulations.

The structural strength given by the ply cladding is amazing.

The only drawback is you can feel the whole frame tremble when someone slams a (very heavy solid oak) exterior door :-)

The exterior could have as easily have had weatherboards instead of the render/mesh. There is no structural strength in the render - its purely there to keep he driving rain off.

[Doctor Drivel]

When it comes to installing insulation sticking to the regs is silly as they are so poor. Always go over by a great margin, and fits as much as you can in.

[Doctor Drivel]

With those single glazed windows you put in?

[Doctor Drivel]

A double brick cavity wall? A dwarf wall?

12" ?

There is a huge cold bridge via the studs.

Which was pretty poor.

[Doctor Drivel]

But doesn't a fridge stay cold actively? The only way an insulated room could cool itself when warm outside would be air con surely. brickwork can get very warm indeed.

Yep. The thermal mas absorbs heat and gives iot back off at night when the temp cools.

With insulation under and to the sides up to the top of the cement screed.

Yep.

[Tim Lamb]

In message , The Natural Philosopher writes

Right.

When my farmhouse was *re-modelled* the specification was ....feather edge or cement render on expanded metal over 25mm foil backed insulation between battens. Then a vapour barrier over the original render (they had to grit blast off the paint to restore permeability). The 4" stud work and lath and plaster were left alone. I doubt it would meet current regulations but it is !"£$%^& warmer than it was:-) I claim to have originated the tale of the hot water bottle that froze on the bedroom floor.

12"?

Oh. I have been considering an internal steel frame to strengthen a 2 storey barn and wonder if this might be an issue.

Huh! I am rebuilding a redundant cowshed and have found that the internal render was actually supporting the roof. Around WWII the ministry of agriculture decreed that dairies should have a white, washable internal surface. This was most easily achieved by nailing up mesh, slapping on a coat of the hardest render possible and giving it a coat of whitewash. What nobody foresaw was the effect of shutting off ventilation from untreated timber. The Oak studs and sole plate are more or less intact but the wall plate (pine) has simply disappeared.

regards