Damp proofing top of new French doors

[diynotuseruk]

Have replaced a window with French doors

I have noticed the steel above the door is slightly damp on the inside, there is an inch gap which I need to plaster so am concerned it will cause damp through the plaster

Was thinking of covering the steel with silicon or sticking some damp proof membrane over the exposed steel and then plastering over the membrane?

Any ideas?

 

[Notch7]

Have replaced a window with French doors

I have noticed the steel above the door is slightly damp on the inside, there is an inch gap which I need to plaster so am concerned it will cause damp through the plaster

Was thinking of covering the steel with silicon or sticking some damp proof membrane over the exposed steel and then plastering over the membrane?

Any ideas?

Is it a conventional catnic style lintel? In which case Im guessing the visible part of metal is the back of the outside section of lintel that supports the external brichwork. The door frame must be quite far forward as usually it would be more or less in line with the back of the lintel. Is the outside thicker than normal -rendered for example.

I image what you are seeing is condensation on the cold lintel rather than damp.

 

[diynotuseruk]

I’m not sure on the lintel style, it’s a 2006 persimmon house if that helps?

The doors are sitting an inch more forward than the window was so they lined up with another set of doors further along

Yes I believe it could be condensation, just not sure of this will cause a damp issue if I fill the 1 inch void with plaster as the plaster will be touching the lintel?

 

[noseall]

The doors are sitting an inch more forward than the window was so they lined up with another set of doors further along

You should have moved the other set further back in. Now both sets are in the wrong position. Any door/window should be set far enough back in towards the interior so that none of the external leaf material is visible from the inside, including any jamb masonry.

You will need to cut the seal at the top of the door, lip some dpc under the door head and cover the exposed part of lintel as best you can. You are always likely to get cold bridging all around the jambs at this point (masonry included), especially during periods of cold weather.

 

[endecotp]

How about filling the gap with expanding foam, rather than plaster? It will provide some insulation, so the internal surface may not get cold enough for condensation to form.

 

[noseall]

How about filling the gap with expanding foam, rather than plaster? It will provide some insulation, so the internal surface may not get cold enough for condensation to form.

There is no gap as such. What you can see along the header is the painted black lintel and the polystyrene lintel insulation.

 

[endecotp]

There is no gap as such. What you can see along the header is the painted black lintel and the polystyrene lintel insulation.

Below which there is a 1-inch gap which he intends to fill with plaster.

 

[noseall]

Below which there is a 1-inch gap which he intends to fill with plaster.

He'd be better off removing the header plaster altogether and dabbing a piece of plasterboard to the head whilst keeping the daps away from making contact with the affected area.

 

[diynotuseruk]

Thanks for the replies

The other door was existing from build so wanted to match it, however the window was more recessed for some reason

Plan on thinking of:
I still have a 1cm gap along the top of the new doors, I can easily put a damp proof membrane in and stick it to the exposed underside of the lintel. Once set silicon the gap at the top of the door to seal and reduce draughts and dot and dab a small piece of plasterboard to the new lintel membrane so I can fill / plaster the gap between the door and existing plaster. Does that sound good enough to do the job?

I could remove the header board and fit a new one, would be a pain to do though as I would need to remove a fair bit of board in the surrounding area, however wouldn’t the condensation drip onto it