External Vent Heights...

[Mulberry View]

In the ever-growing list of c'ockups, I'm fearful of another.

 

This is how our Architect detailed our Foundation build-up, I'm specifically thinking about the sub-floor vents at this stage. Is it normal for them to be positioned at this height? (i.e. the top of the vent level with FFL)

 

 

We have various ground-levels around the building, but that's the height I put all of ours relative to the levels in that part of the building.

 

So, what is the intention where level access is needed?

Edited Monday at 18:04 by Mulberry View

[nod]

They should sit directly under the dpc To allow the telescopic vent to funnel the air down under the block and beam 

[Russell griffiths]

What difference is it making, they are a bit high, are you thinking the area of level access will cover them, I purposely left ours out in the area of the disabled ramp. 
yours are probably better high if you are talking about patio area, as you don’t want them underground. 

[Mulberry View]

12 minutes ago, nod said:

They should sit directly under the dpc To allow the telescopic vent to funnel the air down under the block and beam 

 

Yes, so although I don't have a DPC in the conventional sense, that's in essence what I have.

 

So, back to my original point, how would we provide a paved level access around a front door area if there are vents that sit level with internal FFL? In the picture you've posted, you patio area is presumably 150mm below the internal floor level?

[nod]

I can tell you how I’ve done it 

I’ve stepped the dpc to allow for the extra height of the paving and made sure that placement of vents take this in to consideration 

[Mulberry View]

9 minutes ago, Russell griffiths said:

What difference is it making, they are a bit high, are you thinking the area of level access will cover them, I purposely left ours out in the area of the disabled ramp. 
yours are probably better high if you are talking about patio area, as you don’t want them underground. 

 

We have a 'courtyard' area in the lead up to our Front Door. There are a few vents in this area. This is the approach to the Front Door...

 

 

This is the side-on view. I'm pretty sure I'll lose the vent closest to the door, but they are beneath FFL so the whole area cannot be a level hard-standing.

 

[Mulberry View]

6 minutes ago, nod said:

I can tell you how I’ve done it 

I’ve stepped the dpc to allow for the extra height of the paving and made sure that placement of vents take this in to consideration 

 

I can potentially still remedy my situation if needed, but I'm trying to see where, if anywhere, I've gone wrong.

[G and J]

So you’ve one or more vents where you want/need to do a level wheelchair type access (is that part M?).  Is that correct?

 

If so, are there any other vents that serve the void which the threatened vent serves?

 

If there is then might it be ok just to block that vent?

 

If not could you put a drain grill just outside the door with cutouts to allow air to get to the vent?

[Mulberry View]

10 hours ago, G and J said:

So you’ve one or more vents where you want/need to do a level wheelchair type access (is that part M?).  Is that correct?

 

If so, are there any other vents that serve the void which the threatened vent serves?

 

If there is then might it be ok just to block that vent?

 

If not could you put a drain grill just outside the door with cutouts to allow air to get to the vent?

 

Yes, in a nutshell. If you looks at the side-on photo and imagine a hard standing area (for example) level with the front door opening and falling away from left to right, all of those vents are going to be tricky, even the furthest away one will probably still be close.

 

Luckily, with the building having a 68mm outer layer, I could bury a sleeve in the EPS to effectively move the vents up 150mm  It's a bit of a bodge, but it'll be buried behind the brick slips, so I think I'll just suck it up and get on with it.

[Mulberry View]

13 hours ago, Russell griffiths said:

What difference is it making, they are a bit high, are you thinking the area of level access will cover them, I purposely left ours out in the area of the disabled ramp. 
yours are probably better high if you are talking about patio area, as you don’t want them underground. 

 

The 4 vents in that photo will all be affected, as the area was planned to be level with the large front door opening on the left and be some sort of hard standing falling away left-to-right...

 

 

Providing I can use some rectangular ducting to 'periscope' them up another 150mm, buried in the EPS, then I think that's the way I'll go.

 

I'll put it down to another failure by my expensive Architect.

 

 

[Russell griffiths]

 

i have an area that was going to be 150 down, I now like the idea of bringing it up level with the back door, so 4 vents are low, I’m installing these in my paving area. 

[Mulberry View]

8 minutes ago, Russell griffiths said:

 

i have an area that was going to be 150 down, I now like the idea of bringing it up level with the back door, so 4 vents are low, I’m installing these in my paving area. 

 

They look neat, but what stops the rainwater going in?

[Russell griffiths]

Being that you are in bare icf, just hack the foam off and move the vents up, it will all be behind your brick slips, you will also be able to get them to line up perfectly with a full brick that way. 
winner winner chicken dinner. 

[Spinny]

Another approach might be to lower the ground level but only in the area of the air vents, such as along a strip adjacent to the building, such as a strip of gravel or planting at a level below the paved area/ramp which then keeps the air bricks above ground. There is some discussion of this approach, albeit in the context of dealing with the requirement for 150mm between ground level and DPC level and drainage, on paving expert here...

 

https://www.pavingexpert.com/dpc01

 

In the 1930's when our place was built they didn't have telescopic air bricks and our DPC and airbricks are pretty low in the original house, so may have to take this approach for part of our patio.