I need advise…

[MaddieG]

So I’ve recently bought a house- the house is dated back to 1950 and use concrete floors throughout the interior of the bottom floor of the house. When taking off the skirting board it seems the concrete floors aren’t laid up to the wall, leaving a 2cm gap which can be dug down. Question is can we lay concrete in the holes, then lay a DPM then fibre board or do we lay the DPM then concrete the whole floor again? First time buyer here and seem to be finding more and more issues

 

[RegB]

Are you putting skirting back on?

 

[MaddieG]

Are you putting skirting back on?

Yes once the flooring is laid, we are just concerned about damp being caused because there is no concrete floor in the gap

 

[Mark's Dad]

Hi MaddieG,

I had an almost identical situation quite a few years ago after buying a mid 60's bungalow. Found that the skirting boards were going
rotten on the external walls and the internal ones too! The external ones where easier to solve by reducing the ground level outside,
it was almost up to the damp course!

The internal walls were more of a problem. Before 1965 all concrete floors were laid as wet floors and they relied on those thermoplastic
floor tiles to stop the damp coming through.The floors were deliberately finished short of the walls to help stop the wet concrete floor
being in contact with the brickwork and allowing damp to rise up the walls. (After 1965 Building Reg's demanded a water proof membrane
be laid before the concrete was laid down for the floors). The idiot that plastered the walls had let the plaster fall into that same 20mm
gap you have. Plaster wicks moisture like blotting paper and was the cause of the rotten skirting.

I tackled it by hacking the plaster off clear of the floor back to bare brick and then cleared all of the plaster and **** out of the 20mm
gap down to the sub floor. Made sure it it was all cleared out plus vacuumed any debris left down there also. I used thick polystyrene cut
into strips to fit the gap to fill them with something non absorbent. You could also use those canisters of styrene foam to do the same,
just cut it to floor level after its cured. Made good the plaster leaving a 25mm gap above floor level and fixed new skirt board once
the repaired plaster had fully dried off, no need to drive wooden wedges into the wall, that way the plaster gave a better fixing using
wall plugs and screws for the new skirtings.

 

[MaddieG]

Hi MaddieG,

I had an almost identical situation quite a few years ago after buying a mid 60's bungalow. Found that the skirting boards were going
rotten on the external walls and the internal ones too! The external ones where easier to solve by reducing the ground level outside,
it was almost up to the damp course!

The internal walls were more of a problem. Before 1965 all concrete floors were laid as wet floors and they relied on those thermoplastic
floor tiles to stop the damp coming through.The floors were deliberately finished short of the walls to help stop the wet concrete floor
being in contact with the brickwork and allowing damp to rise up the walls. (After 1965 Building Reg's demanded a water proof membrane
be laid before the concrete was laid down for the floors). The idiot that plastered the walls had let the plaster fall into that same 20mm
gap you have. Plaster wicks moisture like blotting paper and was the cause of the rotten skirting.

I tackled it by hacking the plaster off clear of the floor back to bare brick and then cleared all of the plaster and **** out of the 20mm
gap down to the sub floor. Made sure it it was all cleared out plus vacuumed any debris left down there also. I used thick polystyrene cut
into strips to fit the gap to fill them with something non absorbent. You could also use those canisters of styrene foam to do the same,
just cut it to floor level after its cured. Made good the plaster leaving a 25mm gap above floor level and fixed new skirt board once
the repaired plaster had fully dried off, no need to drive wooden wedges into the wall, that way the plaster gave a better fixing using
wall plugs and screws for the new skirtings.

Thankyou for your reply, it feels like we are finding a problem every day at the moment.
I’ve taken the old plaster to just above the concrete floor and will Hoover out all of the rubbish. Just to double check (I’m no good with building I’m sure you can tell) so I’m filling the 20mm gap with styrene foam then should I lay DPM over the whole floor to make sure there is no damp that could affect the skirting board in the future? So sorry to sound thick

 

[Mark's Dad]

Yeah that styrene foam in cans, Screwfix amongst other places have it. Sounds like you've got the idea ok too. Use the foam sparingly as it expands by a huge amount, if I recall rightly it helps to dampen it with a spray of water before it's cured. Once it's expanded and cured it's easy to trim with a craft type knife. So long as you leave the floor tiles intact and/or the
original black adhesive is still on the concrete floor that should be enough of a damp barrier. The styrene is waterproof even after it's cut and will also adhere to the wall and concrete
either side of the gap so I don't think there's any call for a DPM. If there's bare concrete anywhere you can apply a bitumastic paint to be sure. Alternative is have the whole floor up but you shouldn't need that unless you got damp coming through or the floor is breaking up.
You don't sound think at all! Admire you for having a go and being willing to try. Never hurts to ask for advice, we all have to at times it's how I landed here a few weeks ago.
Good luck with it Maddie.

 

[MaddieG]

Yeah that styrene foam in cans, Screwfix amongst other places have it. Sounds like you've got the idea ok too. Use the foam sparingly as it expands by a huge amount, if I recall rightly it helps to dampen it with a spray of water before it's cured. Once it's expanded and cured it's easy to trim with a craft type knife. So long as you leave the floor tiles intact and/or the
original black adhesive is still on the concrete floor that should be enough of a damp barrier. The styrene is waterproof even after it's cut and will also adhere to the wall and concrete
either side of the gap so I don't think there's any call for a DPM. If there's bare concrete anywhere you can apply a bitumastic paint to be sure. Alternative is have the whole floor up but you shouldn't need that unless you got damp coming through or the floor is breaking up.
You don't sound think at all! Admire you for having a go and being willing to try. Never hurts to ask for advice, we all have to at times it's how I landed here a few weeks ago.
Good luck with it Maddie.

Looks like this will be my weekend project! I now know where to come when I need help! Thankyou again for your much appreciated help and support x

 

[Mark's Dad]

Just an after thought on this. Makes sure you remove/dig out any plaster that's in that gap it will just attract moisture, you may have go down several inches using something like an
old long flat blade screwdriver to get down in there.

 

[MaddieG]

Just an after thought on this. Makes sure you remove/dig out any plaster that's in that gap it will just attract moisture, you may have go down several inches using something like an
old long flat blade screwdriver to get down in there.

Perfect thankyou, I must admit I started yesterday so will dig until clear of any loose plaster, thankyou c

 

[Adam Routley]

You will have a plastic membrane under your concrete slab about 120mm down from finished floor level. And those tiles that you have there are the thermoplastic as a secondary damp provision.

Your lack of wall insulation will cause your inner block walls to be cold to the touch, so when you're breathing in the house, condensation is formed. Naturally, your skirtings being wooden, will hold warmth so on contact with cold walls and the added breath your expelling will eventually cause moisture equaling mould if not cleaned.

The only way around it is to add adequate ventilation to the property or improve the external envelope.

I know all this as I live in a 60s bungalow which I'm renovating. I've also worked within the technical department for several years for many national housebuilders.

 

[Mark's Dad]

You will have a plastic membrane under your concrete slab about 120mm down from finished floor level. And those tiles that you have there are the thermoplastic as a secondary damp provision.

Your lack of wall insulation will cause your inner block walls to be cold to the touch, so when you're breathing in the house, condensation is formed. Naturally, your skirtings being wooden, will hold warmth so on contact with cold walls and the added breath your expelling will eventually cause moisture equaling mould if not cleaned.

The only way around it is to add adequate ventilation to the property or improve the external envelope.

I know all this as I live in a 60s bungalow which I'm renovating. I've also worked within the technical department for several years for many national housebuilders.

Sorry Adam but I have to disagree with your comment about there being a plastic membrane beneath a 1950's build concrete floor. As previously stated I owned a bungalow bu in 1964 which definately didn't have any plastic underneath the floors. 1965 saw the first requirement for DPM's under the newly introduced Building Regulatiuons. I was lucky, apart from sorting out the
gap and plaster dropped in it (causing damp skirting), but didn't have any other issues. My nieghbours did however have problems, their floors dropped and failed and they had new concrete floors laid with DMP's installed. They confirmed that all the properties we lived in all had what are known as wet floors with only the thermoplastic tiles and bitumen to keep the floor dry, They had their floors replaced some years before I moved into my property.
Your bungalow was likely put up after 1965 or the builder was one of a rare breed, knew about the forth coming requirements for DPM's and choose to lay a floor on plastic membrane. I've owned 2 properties in the past that were erected in the 1930's that had true wet floors with quarry tiles in the kitchens, my 1964 bunglow and my first house purchase was a 1975 newbuild ( £7150.00, can't buy a run around car for that now) which did have a DPM and thermoplastic tiles, watched it being built in fact. And yes I'm an old git! .

 

[Adam Routley]

Sorry Adam but I have to disagree with your comment about there being a plastic membrane beneath a 1950's build concrete floor. As previously stated I owned a bungalow bu in 1964 which definately didn't have any plastic underneath the floors. 1965 saw the first requirement for DPM's under the newly introduced Building Regulatiuons. I was lucky, apart from sorting out the
gap and plaster dropped in it (causing damp skirting), but didn't have any other issues. My nieghbours did however have problems, their floors dropped and failed and they had new concrete floors laid with DMP's installed. They confirmed that all the properties we lived in all had what are known as wet floors with only the thermoplastic tiles and bitumen to keep the floor dry, They had their floors replaced some years before I moved into my property.
Your bungalow was likely put up after 1965 or the builder was one of a rare breed, knew about the forth coming requirements for DPM's and choose to lay a floor on plastic membrane. I've owned 2 properties in the past that were erected in the 1930's that had true wet floors with quarry tiles in the kitchens, my 1964 bunglow and my first house purchase was a 1975 newbuild ( £7150.00, can't buy a run around car for that now) which did have a DPM and thermoplastic tiles, watched it being built in fact. And yes I'm an old git! .

The original planning permission (I have the original ticket) was granted in 1958 and subsequently built in 1960. I have thermoplastic tiles as well as a plastic membrane underneath the pad. Judging by the build quality and that of my neighbors (complete mirror property), we clearly had our bungalows built by proper builders.

 

[Mark's Dad]

Glad you had decent build

The original planning permission (I have the original ticket) was granted in 1958 and subsequently built in 1960. I have thermoplastic tiles as well as a plastic membrane underneath the pad. Judging by the build quality and that of my neighbors (complete mirror property), we clearly had our bungalows built by proper builders.

Glad you had decent builders put your house up Adam. Of course planning permission and building reg's are different beasts.
Dolphin Homes (I believe) put my old bunglow up on a large estate in the West Midlands (Wark's back in the 60's). Very unusual and attractive design but they employed a lot of cowboys.