Solid Brick insulating the hallway around the stairs.. ?

[Nogsx3]

We've got a 1950 build solid brick semi detached house. The hallway is always cold and is the largest room facing an outside wall and never gets any sun on it .

We need to re-plaster so we were was thinking about putting up insulated plasterboard. We don't have much room to loose but it starts at 22mm for Knauf Thermal Laminate which has a u value rating of 0.038.

We could only easily fit in the hallway ground, first floor and above the stairway. Would this cause problems as it wasn't a complete coverage off the wall ? We could do under the stairs as well but we'd have to work around the stairs so you'd have a strip where nothing would be insulated.

The roof and floorboards are fully insulated already and external solid wall insulation is very expensive.

 

[pinenot]

Have you considered hemp plaster, applied to the hard this would negate loss of room. The U factor achieved, might not match that of a full blown applied internal insulation, but the fact that extra ventilation is unnecessary might just make that up!

This is quite a read but worth it, especially the conclusion...enjoy...pinenot

http://www.salford.ac.uk/__data/assets/pdf_file/0017/142415/052-Wright.pdf

 

[tony1851]

That report plays heavily on carbon emissions and all the usual climate paraphernalia. One assumes the OP just wants a warmer hall rather than a mission to save the planet.
Would hemp plaster be any easier or cheaper? I doubt it. Kingspan on an internal wall is an easy DIY job; plastering as described in that report won't be. They probably wouldn't notice that much of an improvement in comfort, and it would probably take until 2450 to pay for itself.
Nothing wrong with Kingspan dry-lining.
(OP says 1950s build but solid brick; unusual for that age- usually cavity walls).

 

[Nogsx3]

Thanks for the info, we are after a cheap (relative) and easy solution to get the walls into a better condition and insulate.

The house is of an older design solid brick for the period it built.

Is it not worth worrying about the stairs in the way ? I guess its the same a floorboards which you don't take up and insulate the wall between floors. I was just wondering about 'cold bridging'. Knauf 22mm comes with a vapour barrier and no damp issues currently.

 

[tony1851]

Obviously the stair string will be in the way. All you can do is to finish the board at the top of the string (at an angle, of course) and cut a thinner piece of mdf or similar step-shape to bring to the same thickness, and then just glue some thin decorative trim on this.

Don't bother about insulating the wall within the depth of the floor; it won't let too much vapour in.

 

[pinenot]

That report plays heavily on carbon emissions and all the usual climate paraphernalia. One assumes the OP just wants a warmer hall rather than a mission to save the planet.
Would hemp plaster be any easier or cheaper? I doubt it. Kingspan on an internal wall is an easy DIY job; plastering as described in that report won't be. They probably wouldn't notice that much of an improvement in comfort, and it would probably take until 2450 to pay for itself.
Nothing wrong with Kingspan dry-lining.
(OP says 1950s build but solid brick; unusual for that age- usually cavity walls).

And that my friend is where your advice comes tumbling down around your ears, solid brick built.

First - whilst there's no damp issue at present all research suggests and I've seen so often myself, internal insulation directly to a wall in these circumstances will incur condensation, that's why its fitted to framing (the alternative would be dot dab) both of which provide a cavity for condensation to form on. This allow for an air gap behind the insulation to allow the formed condensation somewhere to form. and dry. I've some designs that call for a gap to be left at the skirting and head of the insulated plasterboard to allow for just such a ventilation system.

A cavity allows air to circulate within it, this in turn dries both brick surfaces inside the cavity which in turn allows the wetter inner condensate'd brick surface to be hygroscopiclly dried via the positively vented cavity...phew, what a mouthful
Kingspan themselves in a report on a similar insulating project, such as your own - Camden House, London - did exactly this, using Kooltherm K 18 insulation plasterboard on wall battens.

My advice was re your statement "We don't have much room to loose" and no ~ despite others rants, it will not cost the earth, in fact there is a co. called Womersleys relatively close to your local, why not give them a call and find out for yourself the cost... http://www.womersleys.co.uk/...pinenot

 

[tony1851]

Pinenot;
With respect, I think one is being a little too anal about this.
K17 can be applied direct to 9" walls - it has its own vapour barrier.
We've done a lot of refurbishment work in the recent past on older Victorian properties (solid 9" walls) being converted to student lets. We just stuck 12.5 plasterboard direct to the walls after stripping the original plaster. We did not even use insulated board; none has caused any problem.
If the OP's wall is in reasonable condition and the pointing OK, he shouldn't have any problems.

 

[AronSearle]

Yes, I don't understand where the condensation risk is pinenot?

And insulation installed with an open cavity to the room for airflow, I think I can spot a small flaw with that

If the insulation has a vapour control layer, and it is properly fitted and sealed around edges, moisture should not migrate through the layers to hit the colder layers at an unmanageable rate.

You will run an increased risk of condensation on the uninsulated areas, due to warmer internal temperatures and still cold surfaces, but that risk remains no matter the insulation method.

 

[pinenot]

Interstitial moisture ingress in the form of condensation, will be a problem with many, not all, solid wall constructed buildings, where non breathing internal wall insulation is added. Natural insulation materials (which can breath) should always be used. Plastic based insulation (PIR/ISO etc.) which cannot breath, trap moisture in the walls preventing periodic drying. This moisture comes, in the main from inside the home, by increasing the insulation factor to the internal side of an exterior wall i.e. adding insulation, the wall beneath the insulation will be cooled. Water moisture is invasive, the heavier moisture laden air inside a building will always find an exit route to the external, fundamentally via the walls. This will build up over time an inch or so into the internal solid wall surface, where it will aggressively attack the wall, where it can cause irrevocable damage.

This is not conjectural on my part, but widely accepted by the industry leading research -
http://www.insulationexpress.co.uk/documents/InterstitialCondensationIssues.pdf

http://www.changeworks.org.uk/uploads/SolidWallInsulation_In_Scotland_Report_ChangeworksJune2012.pdf

http://www.superhomes.org.uk/resources/insulating-a-solid-wall/

English heritage offers the following guide re traditional solid built wall insulation - http://www.climatechangeandyourhome.org.uk/live/insulating_solid_walls.aspx

The evidence is abundant, yet some clearly refuse to head this...I wonder why?

I offered the original poster sound advice viz-a-viz breathable insulation/plaster suitable for solid wall construction, others have offered nothing but derisory comments and negativity to my advice, I wonder what nogsx3 will consider the sounder??

Other info re the problems of insulating solid built homes - Dartford local authority - fact sheet ~ insulating solid walls - http://www.projectbook.co.uk/article_165.html[/youtube]

 

[tony1851]

pinenot;

Having actually read through those documents, I can see nothing wrong with the OP's proposals.

The first one, on Marmox, makes the point that it has a vapour barrier - so does Kingspan Board. The insulated boards Marmox was referring to as not satisfactory were probably the older polystyrene plasterboards, which do not have a vapour barrier.

One of the other docs.made the point that the insulation should not be too thick. I would agree with that because thick insulation will insulate the wall too much. But the OP can only use the thin board because of space problems; his 20mm PUR backing foam will be sufficient to retain a bit of warmth in the hall, but not so much as to completely isolate the brickwork from warmth.

It's down to risk and from experience (which is often worth more than theory) I would say that the OP would not have any significant issues with doing what he suggests.

 

[AronSearle]

Pinenot, I only clicked on the first link, but it shows standard thinking.

Vapour barrier = no condensation (simplified version).

You seem to have flipped this on it's head and are claiming more breathable insulation avoids condensation (when the first link shows it causes it), I don't see where you get your conclusion.