How could I cover a hole in a double brick wall?

[sirblew]

Hi,

I've removed a very old oil heater from its place the wall. Now I need to do something about the hole it left behind. The heater shell is quite rusted, so I may need to remove that, but it's attached to a flue outside which leads to the roof. So, if I remove the shell then I'd probably need to remove the whole flue, which becomes a bigger job.

I'd be ok with cutting off some of the protruding metal from the heater shell if it was easy to do, then put some insulation in the space and cover with plasterboard. Would this work?

What other options are there apart from bricking it up, which would be expensive?

See photos of the removed heater and outside flue below.

Thanks!

[MitchellMc]

Hi @sirblew,

Leaving the heater shell in place sounds like a reasonible solution. Start by using a reciprocating saw or angle grinder with a metal-cutting blade to carefully cut the heater shell flush with the wall. Make sure to wear protective gear, as the metal might be rusted and fragile. Once the shell is trimmed, fill the gap with insulation like Rockwool or fibreglass, which will help prevent drafts and improve energy efficiency.

Next, you’ll need to create a timber frame inside the cavity to support the plasterboard. Cut timber pieces to fit within the edges of the hole, securing them into the wall around the cavity. This frame will give the plasterboard a solid structure to be mounted on. Once the frame is secure, cut a piece of plasterboard to fit the opening, then use screws to fix it onto the timber frame. Finish by applying joint tap and compound around the edges, sanding smooth once dry, and painting to blend seamlessly with the surrounding wall. This approach avoids complex masonry work and removes the need to dismantle the entire flue, providing a clean, stable finish.

Another option, instead of bricking the wall up, would be to remove the shell and then fix a piece of fibre cement to the wall. You'd need to ensure it is adequately sealed around the edges to prevent water ingress. Getting a good seal might be an issue due to the joints in the bricks.

Please let me know if you have further questions.

Mitchell

[sirblew]

Thanks, the plasterboard and timber frame idea sounds like a good plan.

What kind of timber would I need for the frame? How would I secure the frame into the wall?

Also, what could I use to cover the gap at the bottom of the heater shell?

[TedBear]

Hi @sirblew 

Another option to consider is to get a quote from a brickie to fill in the hole and render the inside to match the existing wall. It may not be as expensive as you think. If you go that way, removing the old shell and flue is something you could do yourself just beforehand. (If there is a hole in the roof from the flue you could cut the flu off up high and leave the remnants there. Or get another tile if it's a tiled roof. )

It will give you less problems in the long run, from dirt falling down the flue, draughts and the eventual deterioration of the rusty shell. 

It usually doesn't cost you anything to get a quote to consider amongst your options.

[EricL]

Hi @sirblew 

Just to answer your questions, I suggest using Timber Framing MGP10 H2 Blue Pine. Once you've built the frame you can secure it to the brick using Ramset 7.5 x 100mm Galvanised Masonry Anchor Screw. Please remember to drill pilot holes in the brick to prevent damaging the screws. For the gap at the bottom, I suggest doubling up on the timber to cover that space beneath. To seal all the tiny gaps between the timber frame and the brick wall, I suggest using Self Expanding Foam. Please remember to cut off the excess foam with a craft knife once the foam solidifies and cures.

If you need further assistance, please let us know.

Eric

[jsmith11]

Hi Sirblew.

The metal case doesn’t appear to be adequately waterproofed to the brickwork, evident by the exterior timber frame, rust and mould. To do it justice, I’d recommend removing the steel fixture entirely and filling the hole with bricks. The internal drywall looks like cement sheeting or render. If you simply filled the internal hole and didn’t weatherproof the outside, it looks like water would eventually deteriorate the internal repair. If you cannot find the same bricks, you could install colorbond steel flashing and cover the hole with colorbond sheet or similar. If you didn’t want to deal with the roof, more information is needed, but you may potentially be able to cut it off at the soffit.

[EricL]

Hi @jsmith11 

Let me tag @sirblew to make them aware of your recommendations.

Thank you for sharing your knowledge and experience in regards to covering the hole in the double brick wall.

Eric