Insulating under suspended timber floor... maybe?!

[greenstarthree01]

Hi all,

Just had a room stripped back and skimmed, and while deciding on flooring options the idea of restoring the floorboards came up.
They’re not in bad condition so that part of it should be relatively painless (if dusty!) but as we’re on the ground floor we’ll need to insulate.

It’s a suspended floor with air bricks underneath, and a decent height crawl space so shouldn’t have to lift any boards other than a few repairs.
For this most advice is to use loft insulation rolls supported by netting, fitted from underneath.

Just wondered a) What everyone’s thoughts were and if there were any recommendations, and b) There are a few electric cables feeding sockets and central heating pipes under there - if we don’t compress the insulation too tightly are we ok fitting directly underneath these? If it’s going to be netting supported there won’t be pressure on it as there would if we sandwiched it between boards, for example.

thanks all!

 

[plastic_peanut]

Have a look at the recent insulating floor thread in my projects. This was discussed over the last few days and I have shared my experience

 

[greenstarthree01]

Thanks for the link - sounds like you did something similar to my plan, essentially rolls of loft insulation supported by netting. Good to know it can be done!

Did you have to work around any pipes / cables? My instinct is to leave pipes above the insulation (on the warm floorboards side), but cables underneath it, in the under floor void. That way the pipes are protected from frost, and the cables are not covered by insulation?

 

[Burnerman]

It could be an idea to insulate the heating pipes with the conventional tube insulation first?
The cables won’t overheat so no worries there......if the rolls are wide enough, they may support themselves without netting.
John

 

[IT Minion]

Electrical cables in insulation need to be downrated because they are more prone to overheat.

I'd put both the wires and the pipes on the warm side of the insulation, just for ease of access.

 

[greenstarthree01]

Electrical cables in insulation need to be downrated because they are more prone to overheat.

I'd put both the wires and the pipes on the warm side of the insulation, just for ease of access.

In our situation, access would actually be easier from the cold side because it’s simpler for us to get into the void from a hatch than it is to lift the boards to get at a cable/pipe.

I could probably manage this with the cables but the pipes being fixed will have to stay where they are.

The cables are feeding standard sockets, by downrating do you mean limiting the load to less than the standard 13A?

if I did leave the cables in the void, on the cold side of the insulation, presumably that wouldn’t be the case?

@peanut, are you saying cables shouldn’t overheat regardless? Is it a regs thing, just in case?