Upvc window insulation

[Blobber]

If you want it flush it will probably always crack on the joint between the new board and old wall regardless of what scrim or tape is put down the joint, set it back an inch to loose the flat joint, decorators caulk down the corner, fill the screw holes and paper/or paint a desired, the curtains will hide most of the joint

 

[brightspark]

3mil at the top, 20 at the bottom!

not the skim .you must mean keep the plasterboard 20mm up from the floor thats behind the skirting board

 

[Kram]

Ok I havent done plasterboard or stuff by windows where all this needs to be considered!

So I leave a 20mm gap under the plasterboard, which is not skimmed and is hidden by the new skirting?
Im not sure if they intended that but there is a crumbly gap at the bottom of walls hidden by the old skirtings!

 

[brightspark]

the reason a gap is left so any dampness wont be sucked up the board if any is present

 

[gaz1]

Ok I havent done plasterboard or stuff by windows where all this needs to be considered!

So I leave a 20mm gap under the plasterboard, which is not skimmed and is hidden by the new skirting?
Im not sure if they intended that but there is a crumbly gap at the bottom of walls hidden by the old skirtings!

its too stop you picking up crap off the floor with your float when your floating the walls

but you dont have to leave a gap non of the building sites do and the plaster just skims leaving 1" gap from the bottom with no plaster on it

 

[Kram]

Been a few weeks, I got the frame, plasterboard, shelf and insulation done but next job is to skim it, I may do it soon so it can dry.

Im unsure if moisture resistant plasterboard can be plastered directly, or if it needs a coat of primer? I used SBR on the other bit. Im told to score it too, so it has a good mechanical key.
Should I use SBR?

 

[Blobber]

nooooo dont score it! just skim straight over what youve done, bit of tape down the joints 1st

 

[striker]

Don't score or prime!
Too slow to type!

 

[brightspark]

use a bit of sticky unibond eitherside and on the joint use fiberglass tape and just skim

 

[Kram]

Is SBR no good then?
The plaster says to use Thistle Bond it primer on moisture resistant.
I have joint tape.

Also should I skim right upto the shelf?

 

[addjunkie]

Is SBR no good then?
The plaster says to use Thistle Bond it primer on moisture resistant.
I have joint tape.

Also should I skim right upto the shelf?

Id remove the skirting at the sides and the telecoms box and skim the whole wall, yes right up to the shelf

 

[Kram]

Found Fizzy's missing water, its under our carpet!

Carpet was feeling damp. We are baffled if its condesation on the cold floor or some other problem. the very bottom of the plasterboard is slightly higher moisture, 17%, despite the 2cm gap to floor. The frame and rest is all showing about 13%.
Could be moisture from decorating/wall papering, but we did use dehumidifier a bit.

& Thats what 40 years does to a carpet and foam underlay. Its being replaced when the room is ready!

I think I'll remove capet on Tuesday. Then with nothing to wick, it should be more obvious where its from?!

 

[Kram]

I removed 3 foot of carpet all the way accross the room and the floor appeares dry since then, so its confusing.
Wooden frame and plasterboard dont appear damp.

I've just removed the shelf and stuck my hand in there. The plasterboard side is dry, but the pvc side is dripping wet.

The room will have had moist air ut there would have been almost zero airflow to the cold pvc, so could not be condensation?

It looks to me that the pvc is porous and letting water in?!
We have some outdoor PVC paint but Im not convinced that will be enough.

 

[gaz1]

can you tell me what you have done to insulate what you used and its thickness and seal that area up

sealing the top board to the sides is what i mean if you havent you will still have a through flow of air

ignoring the bottom gap as that would only let cold air in

 

[Onoff]

I'd say unusually cold floor meets warm room at the junction that is the carpet. Thinking how lots of us had workshop condensation issues when the temperatures suddenly shot up.

I'll do you a swap. My jerry built lounge extension is floored in 5/8" chipboard. I've gone through it twice like something from The Money Pit!

https://flic.kr/p/2bRiCFs

https://flic.kr/p/2cSVcDW

 

[Kram]

can you tell me what you have done to insulate what you used and its thickness and seal that area up

sealing the top board to the sides is what i mean if you havent you will still have a through flow of air

ignoring the bottom gap as that would only let cold air in

The topboard was screwed down but has a timy gap either side and back, planned to seal the gaps and paint it later on.

The floor tiles appear dry. However in the cracks between the meter goes off the scale.

Heres a pic of insulation.

I didnt cut the ends of the wool, it all squashed in there ok.

 

[Kram]

Got one of the board off and looked underneath. The floor qhere I used leveller is only 10-11% moisture, I guess thats good.
The pvc and that side of the wool is dripping wet, so it all needs to come out to dry off.

 

[gaz1]

thats really helpful

now dry off all you can and this time seal the top as what you have done is allow free air movement behind the insulation with the air gaps

this has caused the damp issue that your now seeing

 

[Onoff]

You need to read up / understand about vapour control layers and interstitial condensation:

https://www.petercox.com/blog/interstitial-condensation/#:~:text=Interstitial%20condensation%20is%20a%20form,and%20ceilings%20of%20a%20structure.

Old housing stock doesn't take kindly sometimes to "over" insulation.

 

[Kram]

I hadnt finished this project but I'd assumed the gaps were small enough to not be a problem for any significant air flow and condensation. Obviously I was wrong.

I got the insulation out and it is wet, particually the left corner, which again makes me wonder if theres another issue..

So once its all dried out, can you see any issue with refitting as it was, and sealing up the gaps for zero air flow to the cold side?