Gap Above Exterior Door Frame

[jfowles]

Just had a new exterior door and frame fitted but above the door there are gaps on either side. The area is hollow so no brickwork and as you can see from the images there are slats + plasterboard.

On the inside, for the larger 5-10cm gap I plan to cut plasterboard to fit the gap, glue (plasterboard adheshive) to the slats, then skim as I have done small jobs with plaster inside the house.

Outside, the gap is thinner and smaller (<1cm mostly) but there is nothing behind the gap, the slats finish above the remaining board so I can really work against something. As per the picture, the gap to right is larger and I was considering maybe feeding glued horizontal strips of plasterboard to then work against that. Any ideas? Also, I have done some lots of filling and some plastering small jobs inside the house but nothing other than filling outside. Can I still use regular plasterboard and multifinish or do I render? They used expanding foam in the gaps on the sides of the door but nothing here, could this be something also to use? The door is under a covered porch area so not directly against the elements but obviously still exterior.

 

[DiyNutJob]

For big holes and gaps mortar is more robust. You can inject mortar using a mortar gun. I am assuming there is something for the mortar to sit on.

 

[opps]

Given that no one is going to be knocking against the interior areas, I would mist it with water and spray in expanding foam. Once cured, cut away the excess and use a decent powder based filler, eg Toupret TX110. Sand and paint.

If the exterior render is painted, use foam, cut away the excess and use an MS polymer such as CT1 (it is a bit like silicone but can be painted).