converting a suspended floor into a concrete floor?

4 years ago I realyed a rotting suspended floor. After a recent check, I've realized that despite my hard work, the new timber joists are affected by condensation and early stages of rot. Someone suggested to install a DPM over the insulation to diminish condensation...the insulation is rockwool tucked between the joists. Another suggestion was about installing an electrical ventilator to keep the joist condensation free.

I reckon the above are a valid points, and maybe there is a way to correct the issue. Yet, I regret not having considered coverting to a concrete floor in the first place...as this is a terrace house and it is difficult to keep ventilated.

I am considering doing a floating concrete floor (not sure if the terminology is correct). In this way the services run just under the floorboards and over the concrete.

what's the best option?

repairing a suspended floor? or converting it into a concrete floor?

Reply to
swimmydeepo
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what does 'realyed' mean?

you need crossflow ventilation if possible, IE vent bricks at the front and back of house and a clear pasageway through under the joists, either by ducting underneath ny solid parts, or dwarf walls (to hold up the joists) with large holes in them, anything less is folly.

not sure what you are on about here...floorboards?

rip all joists and floorboards out, fill in with (compacted) MOT leaving it

300mm short from desired floor level. lay 50mm of sand. lay 150mm of jablite polysytrene insulation on top. lay 1200 gauge visqueen on top. lay 100mm of readymixed concrete on top. Then you can either tile it, use floor leveling compound or any other finish you like, unless you decide to asphalt it, in which case, leave the concrete 10-15mm short.

HTH

Reply to
Phil L

ahh, relaid.

Reply to
Phil L

Concrete floors are layed at the same time as the walls are built and/or structural support columns.

Whilst I am sympathetic to the plight of your floor. The underlying (sorry about the pun) causes of the damp and condensation must be addressed along with repairs.

Reply to
Ed Sirett

What sub-floor ventilation is there? What's the condensation on? What's the floor covering? Are there damp-proof membranes on supporting walls?

Fixing the sub-floor ventilation is probably easiest.

Reply to
Andrew Gabriel

Make this as thick as possible and run insulation up the side of the wall to floor level. Then only the finail finish floor covering over.

Also run conduit in the floor too to run cables. etc.

Reply to
Doctor Drivel

Dear swimmy It is very inadvisable to mix suspended timber and concrete. Unless you design it well you mess up sub-floor ventilation for the non replaced parts

Either do the lot or replace in timber

If I were to replace in concrete my preference is hardcore, hogging, floor, min 4" preferably more Kingspan or the like - UFH - screed But that's just a personal view - many other very good ways

Chris

Chris

Reply to
mail

There is no damp...the walls are dry and the DPC seems to be working ok. The insulations was't properly installed and there isn't enough ventilation....to provide proper ventilation I would need to dig under the concrete floor in the kitcken and lay a air duct. Also the underfloor surface is soil (not concrete), therefore there is moisture coming from there.

Reply to
swimmydeepo

Well, the idea of the conduit was my initial consideration...until I've found out about "floating" concrete floors. They provide the best of both world (apparently): Instead of setting the screed, it involves fixing some battens over the concrete surface and the floorboards on top, so that there is a very low void underneath only for the services.

Reply to
swimmydeepo

Well I agree it isn't advisable to mix concrete with suspended floor. Since the kitchen has already a concrete floor, it makes more sense to revert the present suspended floor of the living room into concrete as well. Ventilation isn't sufficient unless I dig under the concrete of the kitchen floor.

4 years ago, my concern for not going for the concrete option was also about the services (gas, electricity, water and CH all runs under the floorboards). Ducts under the concrete is an option...but I'd rather go for the floating concrete option by having battens (not screed) laid on top of the concrete and floorboards or plywood fixed on top. Or I might well consider using insulation boards instead of screed...
Reply to
swimmydeepo

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