Sealing up hole where fire once was

[Mike_Guthrie]

Morning all.

I have a hole in the living room where a electric fire is fitted. It’s been drafty for some time a I decided to investigate why

Basically when the house was built they have cut a hole in the breeze block and not sealed it up.

They have instead left plasterboard as a finisher but not sealed it

My question is. For the gaps between the outer brick and the breeze can I fill this with fire rated expanding foam to prevent the draft and then reinstate the plasterboard and seal this around the edges

For the rear back of the wall (that meets the outside. Can this be covered in expanding foam to insulate or should I use something else?

 

[Deleted member 267285]

With the draft,I expect this to be or has been a chimney for a gas fire. If it has been then it can be sealed using breeze block, but a vent is a must to prevent damp issue arising. If it hasn’t been used for a gas fire, then you may need a vent, but I’m not 100%.

 

[Mike_Guthrie]

With the draft,I expect this to be or has been a chimney for a gas fire. If it has been then it can be sealed using breeze block, but a vent is a must to prevent damp issue arising. If it hasn’t been used for a gas fire, then you may need a vent, but I’m not 100%.

Thanks Chris. Yes it looks like it has been a gas fire at one point in time. As there is a terminated gas pipe

Would using a foam not allow the air to still move up and around the gap. The gap extends the full length of the house wall (around 15meters) and vertically up to the roof line. This should allow the air to move no?

 

[Deleted member 267285]

It would take a lot of foam, but I don’t see the harm in it, as long as there’s an air flow, hence the vent requirement.

 

[Mike_Guthrie]

I’m not planning on filling the entire wall. Just a small amount between the breeze and the outer wall to stop the main draft. The other idea I had was some kinda rock wool for walls similar to loft insulation. And stuffing that in the gap.

Just anything to stop the breeze coming through the fireplace

 

[tel765]

Can you post pics showing the whole of the chimney breast in the room and a pic showing the chimney breast area on the outside wall?

 

[Mike_Guthrie]

Can you post pics showing the whole of the chimney breast in the room and a pic showing the chimney breast area on the outside wall?

Well it’s not a chimney breast. It’s more a hole knocked in the wall

It’s a modern house. So it’s outer brick / cavity wall with insulation / breeze block then dot and dab with plasterboard.

I think when the house was built they just hacked a very crude hole in the breeze to install a gas fire and fan flue. This was removed before we bought the house. But looking at other like houses around here the house builders installed fan flues on the outside of the brick.

In the living room we have a fireplace surround and mantle on the plasterboard wall.

 

[Mike_Guthrie]

The gap in green is the bit I want to seal off. And also add some insulation to the back brick. As this is a standard brick depth before it hits the outside.

 

[tel765]

If there previously was a gas fire installed - then where did the gas fire fumes go? I cant see any gas pipe or isolator?
You have cavity insulation showing on the two sides and top?
Simply use the same kind of insulation as required, & then fill the opening with block and D&D.
There's no need to vent.
Your type of CWI isn't supposed to fill the cavity, it leaves a narrow cavity gap which is how it should be with that kind of CWI - best not to attempt to fill that narrow gap.
You can see the remains of a couple of cavity ties on the back wall

 

[Mike_Guthrie]

If there previously was a gas fire installed - then where did the gas fire fumes go? I cant see any gas pipe or isolator?
You have cavity insulation showing on the two sides and top?
Simply use the same kind of insulation as required, & then fill the opening with block and D&D.
There's no need to vent.
Your type of CWI isn't supposed to fill the cavity, it leaves a narrow cavity gap which is how it should be with that kind of CWI - best not to attempt to fill that narrow gap.
You can see the remains of a couple of cavity ties on the back wall

The fumes went out a flue that was in the wall. It was removed before we moved into the house. You can see the differnt coloured orange bricks. This is where it was.

An electric fire was then just placed into this hole and the back (what you see in the images) left as is. This basically funnels cold air intro the house from the air gap. Ideally I want to seal the sides and top off so this is not a full on gap and draft to the outer wall of the house.

I can't brick this up fully. I.E re instate the breeze block as the electric fire sits back into this gap and would foul the breeze Block.

 

[tel765]

OK, then using say Celotex GA 4000 insulation, cut pieces to box in sides, top and back wall - use foam to glue & seal the insulation in place.
Decorate as you please, and no venting needed.