Suspended timber floor insulation advice

[truescot]

Before winter sets in, I want to insulate my suspended timber floor (1930's detached house). There is a good 4 feet dry space under the house (there is a concrete base with a damp proof course where there uised to be just earth),so plan to do it myself. Joists are 400mm apart and 125mm deep.

Thinking about using Knauf Loft Roll from Wickes with netting to hold it up, as it comes in the right widths and I have a Wickes nearby. This comes in 100m and 170mm thickness though - am I best using the thicker stuff, therefore filling right up to the underside of the floorboards and letting uit droop down slighly below the joists? Or should i use the 100mm, which would then sit on the netting and allow a gap between the top of the isuation and the undeside of the floorboards (for ventilation?).

And anything else I need to consider?

 

[truescot]

Sorry, new to the forum and just realised there are lots of threads dealing with this so I will see if I can find my answer there.

 

[Mattatooi]

100mm would be fine. If you are doing it from below, you might find it easier to put some wood battons between joists to hold insulation in roughly, and then put netting on after to secure it. Also, what ever you do, do not get cheap netting. Get good quality stuff that is not stretchy and it will be much much easier. Also, you might want to think about padding back of your head, you are gonna be down there for quite some time! And a good quality mask!

Also you should use opportunity to insulate pipes when you are down there.