Patio door threshold

[Paul Lewis]

Hello

I am replacing the flooring in my kitchen/ diner. I will be laying laminte flooring and the floor is both concrete and marine ply floorboard approx 50/50.

When I ripped up the old threshold it exposed this pit. There is a gap between the patio door and the concrete floor which has a dmp fitted. I'm assuming this gap prevents damp coming across into the concrete screed.

My question is how do I fill this gap whilst still preventing damp ingress.

I will be laying laminate flooring.

Many thanks

 

[vinn]

I dont understand your post or what I'm looking at?

The gap is most probably from the time when a breakthrough was made for the patio doors.

Are you saying that half the floor area of your kitchen is concrete and half is ply?
ie. half is suspended and half is solid?
Or is the ply and "concrete" in 50/50 layers with a DPM beneath the lot?
Is the floor in the pics a suspended floor with what appears to be a bit of joist showing?

Could you post a pic from outside showing the outside threshold/sill level with the doors open?

 

[Paul Lewis]

It's half suspended and half concrete the concrete has about 50mm concrete then a dpm.

The picture shows the concrete portion of the floor. There are some screws in the pic which is penertrating the exposed dpm and into the concrete beneath. Then there is the which is about 75mm wide and 75mm deep concrete at the bottom. The gap has pieces of wood which supported the old wooden threshold jammed in (these are rotten though)

I can't get a picture until tommorow but the sill sits below the dmp in the brickwork

Hopefully that's easier to follow

 

[vinn]

A DPM is a damp proof membrane sheet that covers a large area eg. a whole kitchen floor.
A DPC is a damp proof course that sits in a wall - typically the width of the wall - to prevent rising damp in the wall.

It might be easier to explain this way:
Below the solid floor in the pics is soil or earth - then there is concrete that has been laid on the earth - on top of the concrete is a DPM - what kind of DPM: liquid or sheet material? - on top of the DPM was 50mm of sand & cement?

FWIW:
By looking under the suspended floor you will be able to see the depth and layers of concrete or whatever?.
How is the suspended floor ventilated?

 

[Paul Lewis]

Yes so it is concrete with what appears to be a bitumen type sheet or something like that with 50mm of screed on top. The patio door sill sits below the dpc (the thin black line) in the external leaf of brickwork.

The susspend floor part is an extention that was added to the property afterwards. There is a 3 foot tall storage area underneath which is vented with the vent bricks. This is about 4m to the right of the patio doors though.

 

[chappers]

not there to prevent damp, if original would have had DPM lapped under and been screeded up to the door. Is it possible that this was an opening created at a later date.
Think the best you can do now is line the hole with some DPM lapped up to the DPM under the door, fill the hole with concrete and then maybe even a liquid DPM over the top

 

[vinn]

To keep it simple:
Remove all wood and signs of rot & decay from the gap area.
Spray or brush on a fungicide to all surfaces in the gap.
Flop a wide, very generous ripping of plastic into the gap.
If the door has a ripping of DPC or DPM under it then tuck it into the new plastic.
and pour in a bag or two of easi-mix concrete to bring you up to level with the rest of the concrete floor.
When the concrete has set then trim back any excess of plastic sheeting.

 

[Paul Lewis]

That seems simple enough Thanks for bearing with me