How to know if a floor void can be filled?

[martysmarty]

Hi guys.

I am looking into filling the livingroom suspended floor in. I am not sure if i can do this though as i know some floors are suspended for water evap reasons. So i am not sure how i find this out?

I dug out my kitchen floor ready to insulate and screed, and lay the ufh.

While i was there i seen just how bad the floor joists in the livingroom were rotted. I knew they were rotted as we know we uncovered several issues. Bridged cavity walls and no cross ventilation. When we built the extension i had them run ducts in to fix this.

Now iv got closer to the job and we decided to go underfloor heating in the kitchen i am trying to work out if i should just carry it on?

Iv at least got to replace all the beams and flooring as it stands. Granted it will last now the issues are fixed

The void below the floor only seems to be around 400mm so really its perfect to build back up. My main concern is causing moisture to rise up the walls by filling it.

 

[JohnD]

Have you repaired the leak yet?

Tipping concrete over a leak makes it much harder to repair in future.

Yet this is the reason most rotted suspended floors are filled in.

 

[martysmarty]

Hi, sorry mate not sure on what you mean with the leak? Theres no leaks.

The old timber floor was just blocked from venting. Thats been fixed. So if i were to just replace old for new, id probably just replace all the beams and finish covering and put protective isolator caps on the beams. This would still give me a drafty suspended floor unless i insulate between the beams.

Or i upgrade the floor with a concrete pad, insulation and screed and extend my underfloor heating manifold

My worry is that in some house builds they put suspended floors in due to moisture levels under thd floors. As far as we know theres never been any water under there but i dont know how to be sure?

 

[JohnD]

Hi, sorry mate not sure on what you mean with the leak?

Because it's the usual cause of a rotten floor.

Being next to a kitchen, with pipes and drains in the ground, is common.

 

[martysmarty]

there was a lot of reasons the joists rotted. The membrane under the kitchen floor was missing in places and at the perimiter of the concrete it was 3 inches short in most places. We had damp issues due to external ground was bridged over the dpc line a few years back. Also the cavity inside was filled past the dpc plus a lack of crossflow.

All these have since been rectified with no signs of damp in the livingroom. All pipework has been replaced with plastic including the mains with new mdpe due to the new extension. I am confident theres no water leaks. Just a combination of a lot of issues that went a miss year ago before we had the property.

 

[martysmarty]

Off topic bjt just to give an idea of the factors that we can be sure of that rotted those joists, the ground level itself in this kitchen was too high under the concrete pad. Its a good job we dug it up because the ground under it was actually past the inside dpc bridging it. I have had to dig sub soil away to uncover the slate.