I have a small, semi-detached bungalow in which the wooden floors feel as if they need strengthening. There is a sort of slight spring to them, and they don’t ‘feel’ too strong.
Recently we had bedroom furniture built by a carpenter, and he went through the floor in the corner by the outside wall and next door, when a joist simply gave up through rot. Though he replaced this joist, and one other, and then laminated the bedroom floor, as I walk along the window wall towards the corner where he fell through the floor (where our built-in wardrobe now is), the floor creaks and squeaks.

When transiting the living room – which has the front door entering into it, and is a high traffic area – the floor also makes me feel that if my son and I had to jump up and down hard, we would probably crash through that, too.

We also get slugs inside the house, leaving silver trails, which I understand is also a sign of damp. (I can’t believe they live underneath the house on the solum area, but perhaps get into this under floor area via airbricks, or whatever.

I think the entire floor area of the house i.e. hall, living room, and bedroom, requires ripping up, damp-proofing, central heating pipes clad, brand new joists put in (with PVC at ends where they go into the brickwork), possible additional air bricks to improve air flow. Only when this is done, can I then lay new timber flooring – but before laying the actual boards down, I need to know what membrane, if any, I can lay over the joists, and under the boards, so as to seal my living areas off from whatever is underneath.

My tentative plan is to simply empty one room (living room), take up the carpet and underlay, expose the floorboards, remove skirting boards, crowbar up the old floorboards, drop down into the under floor area, remove the joists, and simply leave a large, smelly, open hole space where the living room floor was.

I then want to inspect this i.e. check airbricks have good air flow; that the airbricks are into ducting that passes from the front of the house, through the cavity, and into the under floor area. I don’t want airbricks that simply replace a brick from the wall, and allow air to go through this and vanish into the cavity. The air needs to be directed past the cavity and into the under floor area.

I then want to check all central heating piping is supported, lagged, and not leaking – but lagged with what? Wrapped in Hessian, or polystyrene tubing?

Having done this I want to clear any rubble, detritus, etc from the ground, and check for any sleeper walls. Then check for puddles.

I would like to damp proof this solum area completely – I believe we are getting damp in there from the clay soil – and only once this has been done to my satisfaction, do I ant to renew the joists and flooring, as well as strengthening the floor by using noggins between the joists.

I have been telling my wife this needs doing, but she refuses to countenance it, believing the upheaval will be too much. I believe I can do it in no more than a couple of days – provided I plan accordingly.

I don’t simply want to tear up the old floorboards/joists, and replace with new, and bang them down to hide what’s underneath. I want a dry under floor area, and the job to be done properly – but need advice.

Whilst reasonably competent at DIY, this is a major undertaking which I am a little frightened of. Once I have started, then I will be compelled to finish it, and if I make an mess of it, I’ll wish I’d never have started, and could lose money unnecessarily. I am loathe to call in builders due to cost, and not being 100% certain they don’t cut corners.

Any advise or ideas would be very helpful.

I have all my floor boards up at the moment as I am having underfloor heating fitted and whilst up having treatment and any rotten joists replaced, old pipes, wires removed etc.

One thing you should consider if doing this is to also add some insulation for the ground floor.