How to patch air con hole from interior to external brick?

nik0106

We’ve had an old air con removed and need to patch and paint area under old aircon, as well as patch hole that goes through the exterior brick. I don’t have a spare brick unfortunately. What’s the easiest way to patch this hole?? What materials do we need and how do we do it? We’re in a double brick building. Ducting on exterior will be removed before we repair.  Currently there is some styrofoam stuffed inside. 

JacobZ

Hi @nik0106,

A warm welcome to the Bunnings Workshop community and thank you for your question.

After removing the ducting, to repair the hole in your brick, I'd suggest using Dingo Structural Repair Mortar mixed with Dulux Avista Brick Red Oxide to imitate the colour of the bricks. Mix a small batch, taking note of the ratios to find a colour you like. Allow it to dry to assess the colour before making any adjustments you deem necessary. 

Once you have a mix you are happy with, you can use a Brick Trowel to apply the mortar to the hole, pushing it into the surrounding brick to help anchor it in place. If you can access the back of the brick from the inside, having something to act as a backing piece while the mortar is put in would be worthwhile. Something like a piece of plywood, or even some cardboard should do the trick.

Once the hole is filled, allow the mortar to set a little bit, not fully, but enough for it to retain its shape and then use a Tuck Pointer and your brick trowel to imitate the mortar lines between the other bricks and apply texture to imitate that of the bricks.

To repair the plaster on the inside, give the unpainted section that sat behind the air con unit a good clean and then apply a thin skim coat of Gyprock CSR Less Mess Multi-Purpose Joint Compound, allow it to dry, sand it back and then paint.

For the hole in the plasterboard wall, check out How to Fix a Hole in the Wall for some guidance.

Let me know what you think and if you have further questions, please don't hesitate to ask.

Jacob