Insulation roll between lounge joists

[Rudie]

Hi I’m planning on lifting the ground floor floor boards with a view to laying insulation rolls ans/or insulation slabs (not cellotex) in between. My dilemma is whether to use garden netting as I’ve read on one post here or wooden strips battens screwed to the bottom of the joist, both methods to prevent the insulation dropping through.

Any advice or recommendations welcomed.

Thanks in advance.

 

[nero44]

Both methods work equally well / bad depending on access. Wooden battens I would think is more work, but both can over time come lose and start sagging. If you haven't source the insulation slabs yet, I recommend rockwool. It's very easy to cut and fairly rigid. Rigid enough that it will actually say in place w/out any netting or wooden battens. For netting, I would recommend using a cordless stapler. Still a faff to fit imo....

 

[Rudie]

thanks @nero44

i do have some breathable membrane left from a previous project which i cud staple in like u say and lay the insulation on top of it?

 

[nero44]

Yes that's also a good way. If you have access from top it will make it much easier... I've insulated my groundfloor via crawlspace below and it's a pain. In some areas my chest was touching the joists.

I would also take that opportunity to clear any debris/rubbish that you have there so the area below the insulation is unobstructed for airflow comine in and out via your airbricks.

 

[aveatry]

Yes that's also a good way. If you have access from top it will make it much easier... I've insulated my groundfloor via crawlspace below and it's a pain. In some areas my chest was touching the joists.

I would also take that opportunity to clear any debris/rubbish that you have there so the area below the insulation is unobstructed for airflow comine in and out via your airbricks.

Sounds exactly what I did, I had to also remove a section of dwarf hit and miss wall so I could "break into the next section. I pushed the rockwoll in as a tight fit from inside the crawl space and then stapled wire across the joists in places.
I also cleaned out all the debris from under there for maximum air flow.

 

[Rudie]

Ok thanks
I’ll use the breathable membrane I have and use the insulation roll and insulation slabs to the height of the joists
I may get the telescopic plastic air vent tubes so the insulation doesn’t block the airflow underneath in case the insulation moves/expands