All in one insulation/wallboards

[ban-all-sheds]

I'm considering lining the inside surface of an external wall in my house - it's solid brick, rendered & pebble-dashed outside - no sign of any water penetration in the 20 years we've been here...

I can't afford to lose too much space, so while I know it would be better to have insulation, then a frame to create a cavity and then foil-backed wallboard I figure that an all-in-one board glued to the wall has got to be better than nothing.

I'm aware of Celotex PL3000 and Kingspan K17 - are there any other products I can look at?

Do any have clear advantages in any ways over others, or are they all much of a muchness?

And what's the best way to deal with window reveals? Even though I'll be using a minimum thickness board, it will still be too thick to line them...

 

[noseall]

four important (and obvious) factors;

the u value you need to achieve, v's the insulation value the sheets provide, v's the thickness of the product, v's cost of the product.

they can be installed either mechanically or by using dry-fix foam.

window reveals...mmmm...? chop back the inner leaf of brickwork and insulate maybe.....

i am not aware of any superior product only the fact that ALL are bulky.

 

[PerryOne]

Windows are the weak point of a room, I find that modern plastic window frames leak heat in a most undesirable way.
Just take a look at your outside window sill on a frosty morning, you will see that the frost on the cill has melted up to about 3 inches from the window frame. Useless.
Knock the plaster off the inside of the reveal and glue on inch thick polystyrene sheets and wet plaster over. Works a treat.
As far as the walls are concerned do the same, do not use mechanical fixings as these become a heat bridge ands you will be troubled by condensation forming on the heads of the screws or nails, forming grey blobs on the decoration.

 

[^woody^]

Windows are the weak point of a room, I find that modern plastic window frames leak heat in a most undesirable way.
Just take a look at your outside window sill on a frosty morning, you will see that the frost on the cill has melted up to about 3 inches from the window frame. Useless.

I think you will find that current thinking/building regulations, find that plastic frames do not function as thermal bridge like other materials and are desirable

The fact that frost does not form on plastic cills has more tho do with the properties of plastic, than heat rushing out through the frames

To the OP, any PIR/PUR insulator like Celotex/Kingspan/Xtratherm is going to be more or less equivalent, and better than anything else for a given thickness.

For reveals use 12mm Celotex (the other makes do not do any this thin) to remove the thermal bridge and chances of local condensation

 

[ban-all-sheds]

the u value you need to achieve, v's the insulation value the sheets provide, v's the thickness of the product, v's cost of the product.

I'll get the u value I get - I've got no target, just the problem that I can't go to more than 30-40mm thick.

they can be installed either mechanically or by using dry-fix foam.

I plan to glue.

I know I can ask the maker this, but do you know if I can stack them vertically? It's a stair wall, so in one place it's about 4.3m tall, i.e. I'll have one sheet above the other. Does the adhesive just stop the sheets falling away from the wall, or does it stop them shearing off? Will I need battens to take the load of the upper sheets?

window reveals...mmmm...? chop back the inner leaf of brickwork and insulate maybe.....

it's solid brick

i am not aware of any superior product only the fact that ALL are bulky.

A fortune awaits the company that comes up with a 1m²k/w-class product a few mm thick...

Knock the plaster off the inside of the reveal and glue on inch thick polystyrene sheets and wet plaster over. Works a treat.

No vapour control layer?

 

[noseall]

even a 9"solid brick wall has an inner and outer leaf ban. though the headers would need snapping.

dry-fix foam will hold like bu**ery and will support a sheet plus many times its weight. shear will not be a problem.

 

[Deluks]

I'd have thought insulating tilebacker board would be a winner for reveals. At only 10mm thick, a layer or 2 won't get in the way and you can plaster straight onto it.

 

[PerryOne]

Woody, the next time there is a heavy frost, take a look, you will find that on the area close to the window frame the frost has melted and two or three inches out the frost is still there. Its nothing to do with the plastic, merely that the heat is being transferred from inside the home to the window cill.

 

[Deluks]

Surely all materials have the ability to conduct heat. I don't see that a window frame will lose that much of the overall room heat anyway.
It's glass that's lossy in a wall, which would explain why the window and surrounding areas are a tad warmer than the rest of the wall.

 

[PerryOne]

You are quite right compared to the rest of the room, window frames are small in area, but you could think of a room where they can still amount to a lot.

It doesn't end with just the frames because the total area equals the reveals plus the window frames plus the window cills as they are all in contact with each other.

The point being that the windows themselves and the frames and the walls and plaster and the window cills are all joined and equal the coldest places in the room.

For many people that equals black mould.
As the moisture in the room, when the rooms temperature drops, immediately condenses on the coldest places in the room, that fuels the mould spores and gives them an ideal place to grow.

That is why its a good idea to insulate the reveals and save heat and the possibility of growing damp and mould and pneumonia.

 

[^woody^]

I don't think so

Mould relates to condensation, which relates to evaporation and dew points and not specifically temperature and cold surfaces

 

[PerryOne]

The air everywhere is full of mould spores, they are not normally a problem, until they find a damp place to land.
Once in place, as long as they are damp, they will grow, mature and produce more spores.
If the location dries out, then they die.

The typical reveal is an ideal place for mould to grow during the cold periods of winter. Once the warm dry days of summer come they often die deprived of damp.

A typical scenario is, a warm humid room where the water vapour is held in suspension until the heating is either turned down or turned off.
At a lower temperature the air cannot hold the same amount of water vapour so it migrates into or onto the nearest cold place.

In most rooms the coldest place is a window, window frame or reveal, that is why, once the outside temperature drops below 11 degrees C, windows start to mist up, as the rooms heat migrates from the room and lowers the temperature.

This is ofter exacerbated inside the reveal once the curtains are closed, which invariably stops the passage of passing warm air that helps to counter the cold from the outside during the day.

As the outside temperature drops, the condensation on the window becomes more noticeable, until it is running down the glass.

In northern Canada for example, once winter sets in, windows mist /freeze up and you often cannot see through them until the following spring.

 

[ban-all-sheds]

OK - change of plan.

The original idea was to do something about the whole side wall of the house (semi - the front/back wall where the stairs run).

The real immediate problem is the bit in the hall where we hang coats - because its cold and the coats stop air circulating we get bad condensation, mould on the wall and the coats.

On the rest of the wall although it's cold and we are losing heat through it we don't have a condensation problem.

I was interested in the all-in-one boards for space reasons as said, but now I think I'll go for a quick fix to the problem area and consider alternatives for a longer term solution for heat loss like adding cladding to the outside.

In the hall section I do have more space (not at home now, but from memory it's 70-odd mm), so I was going to fix battens, put in insulation, then a vapour check layer and wallboard or foil-backed board.

Q - should I fill the entire space with polystyrene/rockwool/whatever, or should I leave an air gap between the insulation and the warm side?

 

[Deluks]

No need. Remember to use foily PB though.

 

[ban-all-sheds]

Any reason to prefer that over polythene?