Concrete floor problem, question

Guru Maith Agut

So I decided to find out why there was a strange musty smell in our hall after a few days of not being home.

Lifted the old wood floor, which I may add had some very strange dark staining on it even after being sanded back a few months ago. I assumed it was a damp issue but wasn't sure until I pulled a few boards up.

Attached pics show the strange way they attached the wooden boards to the floor.






Was this a regular activity back in the early 80's? Planks set into concrete to fix to..??


Anyway, a lot of the boards were badly rotten and like balsa wood to press into. Others were fine, but the whole floor will be coming up now.


So my question is..

What should I put down before fitting new laminate (10mm thick) floor to save against future damp issues?

Should I use a leveling compound to fix the dips and gaps in the current surface and how easy is this to get right for a novice?



Thanks in advance!

my3cents

What it looks like is that you had a suspended floor and then for some reason someone decided to fill it in with concrete. If that is true given the daftness of what has been done its very likely that there is no damp course under the concrete so the only solution is to dig it up and replace it. You might get away with chiseling off say 6inches of the concrete putting in some kind of DPC and then new concrete and a finish of your choice.

In the 80's? Anything could have happened.

dathi

my3cents wrote: »

What it looks like is that you had a suspended floor and then for some reason someone decided to fill it in with concrete. If that is true given the daftness of what has been done its very likely that there is no damp course under the concrete so the only solution is to dig it up and replace it. You might get away with chiseling off say 6inches of the concrete putting in some kind of DPC and then new concrete and a finish of your choice.

In the 80's? Anything could have happened.

there could also be a leak from your central heating rad

Guru Maith Agut

dathi wrote: »

there could also be a leak from your central heating rad

Well we had the central heating system checked by a plumber when we moved in and he said all was fine and that if there was a leak there it would be noticeable in the system.

But that had been a concern for us too before we had him out. Thanks

my3cents

There was possibly damp to start with and rot in the joists, the concrete was dumped in there to stop the floor collapsing into the void space below.

Thats probably why they left the joists and also to make it easy to level up.

Jamemid

Floors in my parents are exact same as this as are all in the estate. House built in 70's.

my3cents

Jamemid wrote: »

Floors in my parents are exact same as this as are all in the estate. House built in 70's.

Good point if you look at the OP's joists then you can see there looks to be only one set of nail holes so not like the floor boards have been taken up and then put back. When the OP said 80's I took him at his word but 70's was in my mind straight away as I've seen no end of crappy building work and "modernisation" that was done in the 70's.

I still doubt there is any damp proofing below the concrete if there was it would probably show around the edges but depends on where the dpc is in the walls.

OP the rest of the house isn't mass concrete is it?

Jamemid

my3cents wrote: »

Good point if you look at the OP's joists then you can see there looks to be only one set of nail holes so not like the floor boards have been taken up and then put back. When the OP said 80's I took him at his word but 70's was in my mind straight away as I've seen no end of crappy building work and "modernisation" that was done in the 70's.

I still doubt there is any damp proofing below the concrete if there was it would probably show around the edges but depends on where the dpc is in the walls.

OP the rest of the house isn't mass concrete is it?

What price would you be looking at to dig up and put down damp proofing,roughly 30sq metre.

Calahonda52

Guru Maith Agut wrote: »

Well we had the central heating system checked by a plumber when we moved in and he said all was fine and that if there was a leak there it would be noticeable in the system.

But that had been a concern for us too before we had him out. Thanks

Open or closed heating system, if open you wont be able to tell

Guru Maith Agut

my3cents wrote: »

When the OP said 80's I took him at his word but 70's was in my mind straight away

House was built in 1983 to be precise. I know that to be fact as we have seen original planning app. and build date.

my3cents wrote: »

OP the rest of the house isn't mass concrete is it?

This floor that I lifted is below level of all other floors throughout the building. All other floors are finished with some form of screed/leveling compound. This I know because we have carpeted and had laminate floor fitted in all but this area of the house.
Only reason I decided to tackle this floor now was because my wife has a strange habit of changing her mind about decor, for some inconceivable reason . . . :rolleyes:

Guru Maith Agut

Calahonda52 wrote: »

Open or closed heating system, if open you wont be able to tell

It's a closed system Calahonda52. Plumber knows what he's about too as we have used him in business for many years.

my3cents

Guru Maith Agut wrote: »

House was built in 1983 to be precise. I know that to be fact as we have seen original planning app. and build date.




This floor that I lifted is below level of all other floors throughout the building. All other floors are finished with some form of screed/leveling compound. This I know because we have carpeted and had laminate floor fitted in all but this area of the house.
Only reason I decided to tackle this floor now was because my wife has a strange habit of changing her mind about decor, for some inconceivable reason . . . :rolleyes:

So is it possible all the other floors are the same but the level has be lifted by just screeding over the problem.

listermint

my3cents wrote: »

So is it possible all the other floors are the same but the level has be lifted by just screeding over the problem.

This.

Guru Maith Agut

my3cents wrote: »

So is it possible all the other floors are the same but the level has be lifted by just screeding over the problem.

Yes I guess that could be possible, but apart from ripping up seemingly good floors to find that out it's impossible to confirm.


Anywho, I have now just laid 12mm plywood on top of the floor and screwed them into the sunken boards and I'm going to lay the new laminate floor on top of that. I have put a membrane underneath the ply and will be putting 3mm PE Foam underlay under the laminate.