Cut DPM External Threashold

[DIY 22387]

Hi,

I need some advice on the best way to deal with a cut DPM and DPC on the threshold of the front door.

I had to replace a rotten door frame and water damaged carpet but when I removed them I found some broken screed which, when removed, revealed the DPM had been cut at the frame bottom and the screed put directly on the the perimeter insulation. It looks like they cut the DPM because they knew the screed wouldn't stick to it and would break up.

In the wall the internal block work is laid directly on to the concrete slab, there is a layer of DPC laid from between the slab and the bottom of the internal block and the top of the blue DPC bricks, there is a further layer of DPC going between the top of the fist internal block and the top of the blue DPC brick and the DPM is finished in the same place. There is also a layer of DPC going vertically up the external leaf and wrapped around aperture and that has been cut short of the bottom. Non of this looks water tight in the slightest I've attached some images to help.

The only thing I can think of is to break out the concrete and remove some of the perimeter insulation around the cut DPM, about a brick deep or so, remove the lowest two bricks of the outer leaf aperture, make a tray in the door area bond it to the existing DPM. Put some rigid insulation in that tray and up to the brick work below DPC and fill with concrete. Fit a length of DPC on top of the fist course of blue bricks and bond it to the existing DPC.

Vertically Around the aperture I would need to add some sort of cavity closing which would need to be using done using DPC or a cavity closer and expanding foam as the external wall is not very strait vertically in the inside of the door aperture.

If you need me to take any more pictures or more details I can do.

Thanks for any advice.

 

[23vc]

Apart from the door, is the rest of the screed dry? If the insulation is supported by something solid and doesn’t just push down, I’d break out the top 3-4 inches or so of it, put a trough of dpm in, and pour some concrete in and smooth off level with existing. Then fit cavity closers on the verticals with foam where needed. Then fit new door frame with the new dpm trapped under its cill.

 

[DIY 22387]

Thanks for the reply,

Yes the rest of the screed is dry Picture (IMG_150414456) is a close up of the cut DPM and the left hand side of picture 7 (IMG_184410039) the brown bit at the top of the picture is the cill/threshold.

Inside the vertical the cavity the DPC and tray are a bit of a mess and looks like any damp in there could just run off and probably get in to the house, should I be bonding the the closer to the DPC and DPM or add some shaped DPM to it to direct any damp out.

Also would it be a good idea to add weep vents at either side of the door frame?

 

[23vc]

Off the shelf cavity closers give you your vertical dpc if fitted correctly so shouldn’t need anything additional to it. Can’t see any need for weep vents anywhere, unless you’ve got a cavity tray somewhere (normally above openings)

 

[noseall]

Hi,

I need some advice on the best way to deal with a cut DPM and DPC on the threshold of the front door.

I had to replace a rotten door frame and water damaged carpet but when I removed them I found some broken screed which, when removed, revealed the DPM had been cut at the frame bottom and the screed put directly on the the perimeter insulation. It looks like they cut the DPM because they knew the screed wouldn't stick to it and would break up.

In the wall the internal block work is laid directly on to the concrete slab, there is a layer of DPC laid from between the slab and the bottom of the internal block and the top of the blue DPC bricks, there is a further layer of DPC going between the top of the fist internal block and the top of the blue DPC brick and the DPM is finished in the same place. There is also a layer of DPC going vertically up the external leaf and wrapped around aperture and that has been cut short of the bottom. Non of this looks water tight in the slightest I've attached some images to help.

The only thing I can think of is to break out the concrete and remove some of the perimeter insulation around the cut DPM, about a brick deep or so, remove the lowest two bricks of the outer leaf aperture, make a tray in the door area bond it to the existing DPM. Put some rigid insulation in that tray and up to the brick work below DPC and fill with concrete. Fit a length of DPC on top of the fist course of blue bricks and bond it to the existing DPC.

Vertically Around the aperture I would need to add some sort of cavity closing which would need to be using done using DPC or a cavity closer and expanding foam as the external wall is not very strait vertically in the inside of the door aperture.

If you need me to take any more pictures or more details I can do.

Thanks for any advice.

A new say UPVC door doesn't necessarily need a DPC. The flooring material however does need (contact) protection from the course of bricks below the door.

 

[Ivor Windybottom]

What's the new doorstep made of? If it's plastic then there's absolutely no issue with rot in future.

There's usually no insulation on the inside of a door. The floor slab should butt up to the outer skin, with a DPM between the two. It's an acceptable compromise of the insulation, but necessary so people can get in and out.

You need to cut/dig out the insulation and replace it with concrete. But access to such a narrow gap would be tricky.