AIR BRICKS

[DeletedUser]

I have a 1930's semi and had cavity wall insulation done earlier this year. All the air bricks upstairs were already covered up from the inside, the company that did the cavity wall insulation also filled them from the outside with clear silicone.

The upstairs is now a lot warmer but the front room downstairs is still very chilly. There are three air bricks situated on the bay window about half way up which the company did not touch. Could this be causing the cold? They are not visible from the inside and I was told air bricks are only needed if the gas fire is over a certain rating, is this correct and if so is it safe to fill the bricks from the outside? Is there anything else that could be causing the cold, the entire house is double glazed but I do have two chimneys. Thanks

 

[gas4you]

Gas fire has to be less than 7Kw INPUT to not need any purpose ventilation. It also depends on the type of the fire and the MI's. The MI's always over ride any regulations in force.

The chimneys will be drawing warmth out of the room as well. I always allow an extra 20% on ant rad sizes in a room with an open fire to help against this.

 

[tryitandsee]

Are these air bricks ventilating the floor space under your suspended timber floor?

If so, the cavity wall people should have removed all these air bricks on the ground floor and packed fibre glass (or simular type material) in the cavity to form an opening to allow clear passage of air, from outside to inside floor void. Then replaced airbrick. This packing forms a dam to stop all the 'rockwall' from blowing out from the air brick when they are filling.

It is quite common for them not to bother with taking out and repointing in airbricks, but you really need this passage of air to get under the floor.

Upstairs is easy, they just fill them with clear silicon from the outside.

Make sure you can see the tell tell signs of the cavity having been actually filled in the bay, ie small holes filled with matching mortar. They might have missed it by accident