Batten plasterboard and insulation advice needed on cavity wall

[Chippee]

Hi all, I am in the middle of renovating my house and was going to take the walls back to brick give it a quick light render skim then batten and plasterboard. I have recently had bad cavity insulation removed and now the house feels the cold a lot so I was told I could batten the inside walls and infill between the battens with insulation boards like kingspan etc I would prefer a thinner batten and have no gap between the brick and insulation board. My only question is would this be ok and not cause any damp as I still have an open cavity between the two main brick walls.

Thanks

 

[Jadele]

damp inside a house is mainly caused by condensation. So if you can make your walls warm, keep a good airflow and a low humidity then mold should not be an issue. If you have the above but with areas of little air circulation such as corners or behind wardrobes where it can get cold you will get mold The cavity is there to provide what you may describe as a wet skin and a dry skin of brick work. So the outer brickwork can saturate with water but the water can't get to the inner skin to come through as damp. The cavity shouldn't really be very wet but bad insulation and other building errors can cause paths for water to get to the inner skin where you will see damp. So the method you detail should not cause damp but it may only mask the damp depending on why it was damp in the first place.

 

[Chippee]

Thank you for your help. I understand the reason for a cavity i was just unsure of insulating tight to the inner wall under the plasterboard would cause any other issues with regards to damp. I've read that some people recommend leaving a gap between the insulation board and the wall itself but that was in relation to a solid non cavity wall, but there was no mention if a cavity wall would need the same added gap between the insulation board and innerwall.
Thanks again.

 

[vinn]

Pulling a wall out will give various kinds of knock-on hurdles to be overcome but DIY doable.
You dont need battens.
A good method is to use fixings to pin 40mm insulated or thermal board to the walls.
Mfr's will give installation advice ref any tricky bits.

If CWI has been removed you have to be certain that its all out.
Why did it fail?
Do you have render on the house?

 

[Chippee]

Pulling a wall out will give various kinds of knock-on hurdles to be overcome but DIY doable.
You dont need battens.
A good method is to use fixings to pin 40mm insulated or thermal board to the walls.
Mfr's will give installation advice ref any tricky bits.

If CWI has been removed you have to be certain that its all out.
Why did it fail?
Do you have render on the house?

Hi thanks for the advice the Cwi was causing damp in multiple rooms. A surveyor came and pointed out the cwi was "blown" and needed removing, as it had a 25yr guarantee this was done free. Also the house does have rendering.

 

[vinn]

CWI does not and cannot "blow" - rendering is what blows.
Who was this "surveyor" and what exactly did he do? Did he represent a company that removes CWI?
Did he open up the wall or insert a viewing instrument into the cavity?

Besides the wet CWI you might have snots on the cavity ties?

 

[Chippee]

CWI does not and cannot "blow" - rendering is what blows.
Who was this "surveyor" and what exactly did he do? Did he represent a company that removes CWI?
Did he open up the wall or insert a viewing instrument into the cavity?

Besides the wet CWI you might have snots on the cavity ties?

I think the surveyor meant that the cavity was not solid as there were multiple spots missing the cwi. Basically it was a botch job by cowboys. The whole process was rectified by the Cavity Insulation Guarantee Agency CIGA and once they done their job the council sent out another surveyor and an inspector to check the removel work and damaged caused by the cwi etc using inspection cameras around the whole house. I'm confident in the whole removal process that took place as the inspectors and surveyors were all professional and knew their job well. All my external vents were also changed as the original installers of the cwi didn't properly flush the cavity before installing, and rubble was blocking vents and needed to be removed. I was offered replacement cwi after the removal but I refused as I didn't want to take a chance due to the bad experiance I have already had with the stuff.

 

[vinn]

Thank you - good to hear a good story about CIGA.

 

[Chippee]

So I have now took the walls back to brick and I'm still unsure on the best method and what type of plasterboard to go with in my scenario. I am currently looking at insulated plasterboard and not separate kingspan sheets, but am I best battening this type of plasterboard or dot and dab or can I apply these directly with mechanical fixings? Also I don't know if I would even be better off just to go with regular plasterboard and not the insulated type. I just don't want to cause any issues with the inner cavity wall producing damp as the heat in the house wouldn't reach that wall if I used insulated.
i think I'm just being over cautious as I don't want issues with the walls after the job is done and waste money.

 

[vinn]

As I suggested above, insulated plaster board is doable.
But you apparently still have the issue of your render - has it been blown or is it sound?
And what about the "cavity debris" you mentioned - what, if anything, has been done about it?