How can I move an air brick so it's not at the bottom of a flower bed?

[pedr0]

Hi all,

My air brick 'vents' into the bottom of a flower bed

I've had a typical rear extension on my victorian terrace so that my kitchen has been extended into what was the side return. The suspended timber floor used to have an air brick that vented into the side return. Now that the side return no longer exists, the contractor added some duct from the original location of the air brick to vent out of the side of the new wall.

In the picture below, the air brick used to be below the french double doors that you can see in the top left of the picture. It now is routed beneath the steps and even under the floor so that it vents out of the side wall (the one with breeze blocks in the picture).




However, he put the new air brick below the damp proof course so that it vents directly into the bottom of my neighbour's planter. I.e. straight into the bottom of 2 foot of soil.

I.e. the air brick is burried in the far corner at the bottom of this planter:



The new party wall is a cavity wall with london stock on the outside and breeze blocks on the inside. I'd welcome suggestions as to how I can move that air brick up above the planter.

I know I can get some telescopic cavity vent kits like this, but they are designed to be installed at the time of construction. Can they be retrofitted at all?


Here's a floor plan sketch if it helps:

 

[Lower]

You can get periscope or telescopic type air vents that will attach to the existing vent and then poke out of the top of the flower bed.

 

[pedr0]

Thanks @Lower. The problem with that is that the neighbour doesn't want anything on their side of the party line.

 

[oldbutnotdead]

You can install those telescopic tunnels after building but you'll have to remove a load of bricks from the outer (or blocks fromr inner skin) to do it, plus be careful not to bridge the dpc when you do it

 

[pedr0]

Hmm removing a "load of bricks" sounds pretty horrible. I guess a less graceful alternative might be to have the telescope on the interior, snug to the blocks, and put a plasterboard wall up in front of that. Does that sound sensible?

 

[oldbutnotdead]

If you're happy to chop the plaster or whatever off the inside skin to expose the blocks/bricks it'll be loads easier- no need to point up neatly afterwards. If you've got a decent sds drill, removing bricks/blocks isn't hard. Even easierfrom the inside, you can trash a block and put a new one in (rather than having to preserve face bricks for a match). Losing 200mm of the room would be a shame...

 

[pedr0]

The inside of the wall was never finished. Still exposed blocks. Got an SDS drill.

I have to move the air brick up quite high (maybe 600mm or so). Can I remove more than one block at a time or is that dangerous? Do I need to worry about avoiding wall ties?

The existing duct is below finished floor and lower than the DPC I believe. Can I connect to the existing ducting somehow without compromising the function of the DPC? It would be neater to do it that way, but if not, I could possibly bring the bottom end of the telescope out at floor height on the inside because there are some internal steps that would hide it all.

 

[oldbutnotdead]

Cool. 600mm- get your telrscopic duct first, you may have to do an epic bodge to get that much height difference.
For that height i'd suggest removing 1 block width (so full block at the top or bottom) and then just cut straight down. 1 block width out the wall is fine, if you followed bond that'd be more sketchy (you'd end up with 2 blocks out). If you can avoid wall ties great, if you hit one its not the end of the world.
You want the internal end below dpc, if you have to lap a new bit in it'll be fine, plenty of overlap.

 

[pedr0]

this is really helpful. Thanks @oldbutnotdead .

When I put the blocks back in, should I get new whole blocks and lay them one on top of the other, or should I use the half blocks that I removed and try and recreate the bond?

Never done anything with DPC before, so haven't got a clue about that. I'd best do some research....

 

[oldbutnotdead]

Up to you on the blocks, structurally insignificant. If you're a bit paranoid, when you replace the blocks you'll find getting mortar into the top joint v tricky. Push some bits of slate in the gap, mortar them in (the slate will carry what little load comes thru that joint)​

 

[pedr0]

I just had a glance at the existing duct, and it emerges tight to the old exterior wall. So in order to stick my telescopic vent onto the existing duct means I'll have to remove blocks from the very far left of the new wall - ie the blocks that actually butt up against the old wall. I have been told there's a 'wall starter' there too. Apparently you can just about see it in the gap in the mortar in the photo below.

Does that change anything?