Fine tuning my IWI Solid wall (Warm Batten) design

[lookseehear]

I hadn't heard of gypframe and just looked it up. What do you do if you need a strong wall fixing? The appeal of timber battens is that you can at least screw into it if you need to.

[Annker]

 

3 hours ago, lookseehear said:

I hadn't heard of gypframe and just looked it up. What do you do if you need a strong wall fixing? The appeal of timber battens is that you can at least screw into it if you need to.

Typically you would pattress out areas of wall that are going to have fixtures prior to plaster boarding 

Edited December 16, 2024 by Annker

[Iceverge]

3 hours ago, Annker said:

whatever that means

 

Nothing. 

[Mike]

On 14/12/2024 at 00:54, Mike said:

On 13/12/2024 at 22:17, Annker said:

I'm trying to get my head around is how/will the stud work keep and maintain to keep the insulation against and in full contact with the wall.

Provided you use semi-flexible insulation batts you cut them a little oversize and compress them a little, so that they push gently against each other from floor to ceiling and wall to wall, holding each other in place when supported by the studwork...

Just found a pair of images to illustrate the above. This is hemp insulation on a wall about 1m wide x 2.6m high, self-supporting (left) before I put the studs in place (right). The batts here are 100mm thick, but the lowest (out of shot) was sawn through to about half that as the wall behind was out of plumb.

Edited December 17, 2024 by Mike

[ab12]

On 17/12/2024 at 23:44, Mike said:

Just found a pair of images to illustrate the above. This is hemp insulation on a wall about 1m wide x 2.6m high, self-supporting (left) before I put the studs in place (right). The batts here are 100mm thick, but the lowest (out of shot) was sawn through to about half that as the wall behind was out of plumb.

Mike. This is interesting. How did you manage to fix the hemp flexi batts to the walls? With some sort of glue?

Very much like this concept and the following dawned on me. can everyone please critique this:

 

50mm hemp batts fixed to the wall as shown in Mike's photo's with timber battens above instead of the metal studs shown in Mike's photo's to allow for fixing of  either plasterboard with standard gypsum finish or rigidi fibre board with lime finish.

 

Critically will the flexi batts stay in play independant of the studs.

 

Previously was going to fix timber studs to wall and push fit flexi batts between the studs but Mike's strategy is much better as it allows for continous layer of insulation not broke by the studs.

 

In addition electrical socket back boxes can be fitted infront of the flexi insulation batts.

 

Dunno whether this is eureka moment, atleast appears to be so thanks to Mike's suggestion.

[ab12]

On 13/12/2024 at 21:04, Annker said:

Studwork as required as the current preference irrespective of insulation choice is to plasterboard and gypsum skim finish the walls.

Reason being I can do the boarding myself and then it should be easy to find a decent plasterer to do the relatively straight forward job of skimming (verses finding a lime plasterer)

 

Don't want to dampen the spirit but a point of observation will the gypsum plasterboard and gypsum  plaster finish NOT contradict the breathable element of the make up?

In addition have you thought about paint finish- certified breathable paint with low SD low?

 

The research that I've done suggests, in order to maintain the breathable aspect, instead of gypsum plaster board to use  rigid fibre board say approx 20mm thickness or wood wool boards fixed to the studwork and finished with Baumit 38 or equivalent product which a standard plasterer should be able to cope with. 

 

Also, just checking Ankerr with your setup, will there be a cavity between the plasterboard and the insulation fibre board attached to the wall?

What sized CLS timber studs are you thinking of using?

Thanks

[Mike]

4 hours ago, ab12 said:

Mike. This is interesting. How did you manage to fix the hemp flexi batts to the walls? With some sort of glue?

No glue required - they're just cut a little over length so that they gently wedge themselves between the walls.

 

3 hours ago, ab12 said:

Critically will the flexi batts stay in play independant of the studs.

Short lengths will stay in place until you put the studs in place, or you can slide the batts behind the studs, or a mixture of both - slide just one end of the batts behind a stud, put the batts in place, then the rest of the studs. It depends on the situation.

 

In this photo there wasn't much space to slide them behind the studs so, as there were walls either side to hold the batts well, it was easier to fix the studs afterwards.

 

3 hours ago, ab12 said:

will the gypsum plasterboard and gypsum  plaster finish NOT contradict the breathable element of the make up?

In addition have you thought about paint finish- certified breathable paint with low SD low?

Plasterboard and gypsum plaster are vapour-permiable, so no problem. Vapour won't move through them over the course of a few hours, but it will over the course of days, which is enough. But but it is necessary to use a vapour-permiable paint over the top - see https://forum.buildhub.org.uk/topic/41776-breathable-paints

 

[lookseehear]

I've been looking more into this after taking some plaster and old newtonite off the walls at home. As expected the stone is pretty uneven, but looks pretty dry. This is about 2 feet above the ground.

 

 

I'm thinking about making up my own base layer of lime plaster as a levelling and airtight coat, rather than a cement based parge coat. I was thinking that a 3:1 mix of sharp sand and lime putty (slaked quicklime) with some synthetic hair added is probably the 'best' thing for the walls.

 

I assume this would suffice from an airtightness perspective and would likely be cheaper than bagged alternatives like Baumit and better than a cement based parge from a drying and wall-health perspective. If I'm only using this to roughly level, hopefully I can get it done in one coat and it won't have to be particularly neat.

 

Over this I'd do the aformentioned wood fibre or mineral wool with ~50mm battens or a 63mm CLS stud wall creating a service cavity, then plasterboard and skim. If the plasterboard turns out to be problematic down the line, it would be possible to swap these out for a wood fibre board with lime skim, but I'd hope not to have to do this obviously!

 

Window reveals would also be lime plastered, then lined either with some PIR or somthing like Bosig Phonotherm (https://www.ecologicalbuildingsystems.com/product/phonotherm) or maybe a wood fibre reveal board.

 

Any thoughts on the above? If the lime putty based plaster is sufficiently airtight I wouldn't bother with an intello membrane, and instead would focus on getting the details of the lime plaster and taping to joists/floors etc right.