Under floor Insulation.

Janerox

We have a bungalow that we are about to update before moving in. There is no under floor insulation and a huge draft coming up through the floorboards. It's a difficult space to get into, any advice on how to insulate it.

grumbler

For the draft, just fill all the gaps -  Filling between floorboards

For a proper insulation see this recent thread - Underfloor insulation

Jeepers_Creepers

Janerox, are you planning to lift the floorboards to add insulation, or do you want a solution that leaves it in place?

For the former, that other thread pretty much covers it.

For a hassle-free improvement that obviously won't be as good but will still make a very noticeable improvement, take up the floor coverings to expose the 'boards. Vacuum the grooves, man, and under the skirting boards.

Then get tubes of the cheapest frame sealant or decorator's caulk - it just needs to be cheap and flexible. Solvent-free stuff is easier to use - wipes away with water - but no big deal.

Fill all the T&G gaps and also - more importantly - the gaps around the perimeter between the skirtings and the 'boards; the biggest howlers come through there.

Then lay down - with odd blobs of adhesive (eg solvent-free 'no-nails' type stuff) whatever thickness of low density fibreboard you can get away with, the stuff that's commonly used as underlay for laminate flooring. It comes as thin as - ooh - 5mm, but if you can get away with 8 or 10 or even more, then great. This will mean you'll need to trim your door bottoms, and also have a threshold strip to make the change in level acceptable - so decide on the finished thickness carefully. Even 5mm stuff will make a difference so is worthwhile.

Then just add whatever covering you were planning to use - carpet, whatevs.

Floors are the least important surfaces in a room when it comes to benefitting from insulation, as it's the coldest part of the room anyway so less heat loss through there, but also timber boards are already very good insulators. As you've discovered, the main thing to do is to block the draughts!

OilyByker

We had the same issue with floating floor and large air bricks. We had a survey for under floor but the gap wasn't big enpugh without taking all the floors up. UNTIL we had OVERFLOOR insulation. Pretty new tech fabric that as imprved the warmth in our lounge and bedroom (Bungalow) by adding the new nanotechnology fabric under the carpet and underlay.
Damp proof, breathable and insulated apparently 89% better. Can also be put under plaster of walls.
Cost wasn't cheap, but instant improvement and no drafts at all whereas the carpet was always cold in winter.