How do I fit new airbricks?

[JP_]

OK, so I thought this would be easy. Pics show drill in line with top of other airbrick inside, but very low outside (and going through concrete explains why it was so hard!).Do I just need to dig out some of that concrete so the airbrick is below the outside ground level (and put in some sort of rain cover).

Stick shows that original airbrick in a straight line - for a moment I thought it was offset, higher outside.

 

[John D v2.0]

Your photos are showing as no entry signs here

 

[Keithmac]

Will that not just leak water in when it rains?.

 

[JP_]

Changed photos.
Probably will leak water. But need more airbricks ... will have to rain proof it somehow. I think I'll have to take out some of the concrete path and make a smallish French drain.
I guess the path was raised when the drains were updated at some point in the distance past.

 

[JP_]

Maybe the "air brick to floor" is an easier and better longterm solution
http://www.1stassociated.co.uk/articles/french-drains2.asp

basically, create a little barrier around each air brick to stop water getting in, and then give it a little canopy to stop direct rainfall filling the area.
With good ventilation below, any small ingress of water should evaporate.

Also, I could add a mortar slope on the base on the airbrick channel maybe? So any water pooling there cannot flow up ...

 

[John D v2.0]

In old houses, without intervention, the paths are always far too high. Unless it's a step down into the front door, people laying patios etc will always save time on digging out and disposal.
We had some guy telling us he would do that for us and bring it up to the front door as if it was a good thing! When I told him what about the dpc he said he'd leave a block out in front of the air brick.

Unfortunately for you, like for us, it's a bit of a thankless task digging it all out.
I've left a trench next to the side wall at the moment as I can't remove the shared drive, but I'm planning a channel drain with the top level with the oversite, connected to the surface water drainage. I'm a bit suspicious of French drains as there's nothing to stop them getting silted up and sitting damp in future. The channel drain at least it will be obvious it needs cleaning out.

 

[JP_]

Good idea about channel. Ground slopes to front so water should not hang about.

 

[JP_]

Although, could I either:

1. use a telescopic / periscope airbrick vent, and take out some of the internal bricks to accommodate it
2. Have the periscope outside the wall.

Not seen either suggested as an option, and probably with good reason! But, cannot see anything majorly wrong with option 2 - could be water tight and allow the ventilation I need. I could even dress them somehow to look less naff....


edit .... option done here https://www.diynot.com/diy/threads/replacing-a-bouncy-floor.441362/#post-3458666

 

[JP_]

Actually, maybe fitting a periscope on the outside is not such a stupid idea if I go ahead with external insulation.

Just get these ... https://www.screwfix.com/p/telescopic-underfloor-vent-black-220mm-x-215mm/12025 put them on the outside, ensuring water tight at ground level. Wont look any different once the EWI with render is installed.

 

[^woody^]

You're drilling through the DPC and the bit is coming out below the ground level? Air bricks are not got only problem.

You've got the depth there to throw in a DPM, insulation and screed.

 

[JP_]

you know, I did think about having a concrete floor instead, but it was suggested that cost would be an issue. But if that would resolve the damp and rot problems, assuming the dpm never broke down (how long do they last?) then I'd consider it. Although, how would I get the concrete in ..... through the house, or pumped through the window?

Of course doing one room, or a couple of rooms, would reduce air flow to the rest of the house ..... where would I stop???

How would I know if the concrete path was raised purely due to laziness, or for reasons to do with the drainage down the side of the house? Would a general builder be able to tell me? Or would I need a drain guy to look?

 

[Doggit]

Well spotted on the telescopic air brick Jonbey, but you're going to need to do a bit of cutting on it to be able to fit it in to the height of two bricks; as you need to get the outside up a brick higher than it is, but keep the inside below the floorboards, but Woodys right in the you need to be careful of cutting through the DPC. If you do, then you need to apply some bitumen or similar around the inside of the bricks you remove to reinstate it; can't see where the DPC is, so try marking it on the next picture you post.

And as the air bricks are just about at the joist height, then you definitely need to install a french drain outside, but I'd go for a drain channel rather than gravel, as they're maintenance free, and won't fill with dirt over time and become ineffective. I'd also think about injecting a silicone DPC before the floorboards go back down, but it needs careful setting out in relation to the french drain outside.

 

[JP_]

To be honest, I don't know where the DPC is either!
I am guessing from WOody's comment that it is where the thicker mortar is? The bit I drilled right through ...

Also, that joist in the pic is not the top one - the top one was right across the air brick, and rotten. Which is how all this started!