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Filling holes that go straight from interior wall to exterior

I have some little holes dotted around the house where wiring has been removed. I want to try and fill them in. They are no more than an inch wide. Whats the best way to fill them? Wall filler on the interior and mortar on the exterior till they meet? Some of them are right next to pvc windows and with these I was thinking to put sealant on the exterior in line with the sealant already going round the window. Again would you use polyfiler in the inside then mortar on outside and seal over the mortar around the windows edge when the mortar is dry?

3 Answers from MyBuilder Bricklayers

Best Answer

There will need to be a gap between the external side and internal side so don’t fill in the holes until the mortar and filler meet in the middle, just fill in the internal side with filler flush with the hole and do the same for external side with mortar. As for windows if sealant would work then seal up with frame sealant and decorator caulk or filler on the internal depending on the size of the hole next to the frame.


Answered 20th Mar 2020

If its drill holes or ex cable size holes .. small then you'd be struggling with mortar to go deep enough otherthan making the hole bigger then ok, so mastic of a similar colour or silicone, the difference being mastic you could colour match with the introduction of brick dust or powder paint(the school stuff !) or trial pots (emulsion) , silicone is good but will not adapt in a 'composite' ...appearance not to much of an issue youll find clear silicone less fussy and by enlarge quite acceptable. Inside small holes filler will do, larger holes filler will sink , so will need a repeat once dry and sanded, the other point about not filling the hole inside and out to join up... hmm hello....? a solid 9 inch wall is whole thermal bridge anyway,.. a cavity wall ...well the insulation will stop you or if not insulated it will fall down the cavity !....


Answered 20th Mar 2020

For the internal holes I would recomend a pre mixed lightweight filler as this dries hard and doesn't shrink, red devil is a really good brand to use.
For the external some mortar or frame sealant of the same colour would suffice.


Answered 20th Mar 2020

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