Damp-proof course below 150 mm - is this a problem when selling a house?

[TullioK]

We're having a new patio installed and the builders are doing a great job. However, I'm concerned to see the new level is only 120 mm below the damp proof course in places. The new level also comes about an inch above the bottom of an air brick which doesn't look right and I suppose could increase the chances of water going through.

It's pretty clear that building regulations are for 150 mm minimum, but this work is not subject to building control, so I'm mostly concerned now about the devaluation of the house if this gets flagged by a surveyor in a homebuyer's report, giving a potential buyer reason to reduce their offer.

I've heard that sometimes 75 mm is considered OK and also "a course and a half" is OK. But if anything under 150 mm is going to appear on a homebuyer report then that is problematic regardless of what is considered "OK" in practice.

I have flagged it with the builders who say they have said they'd need to redo a lot of work to lower the level. The job is now not that far from finished and I don't want to make a fuss unnecessarily, but I also don't want this to be a problem down the line.

If anyone has any surveying experience or practical experience of how this issues usually pans out, I'd greatly appreciate your advice. Thanks in advance.

 

[^woody^]

Any surveyor should advise their client that the minimum recommended distance is not achieved, therefore there is a risk.

The client may be prepared to accept the risk with a suitable price reduction to reflect any potential future costs, or the costs of remedying the risk.

Likewise in your situation, you should require your builders to either rectify their work at their cost, or reduce their charges to reflect your future risk.

The cost to you at sale time from a well worded report, in a buyers market could be several thousand pounds.

 

[TullioK]

Thanks, woody, you always have useful advice.

Does anyone have any opinion to the contrary? I really don't want to have to ask for rework but feel like I'm probably left with no choice. Thanks.

 

[blup]

You could live with 120mm but, and it may be too late to change, get the air brick sorted, some kind of telescopic vent is available.

 

[ETAF]

The new level also comes about an inch above the bottom of an air brick which doesn't look right and I suppose could increase the chances of water going through.

But that may do a lot more damage , then the value of the house , if water gets into the airbrick, not sure what the chances are of that - I am NOT A BUILDER - but as a home owner , i would not be happy with that situation , even if not selling...

 

[noseall]

We're having a new patio installed and the builders are doing a great job. However, I'm concerned to see the new level is only 120 mm below the damp proof course in places.

Not usually an issue, especially with a modern cavity construction. Paving may occasionally sneak up above the 150mm mark when achieving ideal falls etc.

 

[johnny2007]

Didn't they have a tape measure when they started the patio?

 

[TullioK]

We've managed to get the level down so it's now below the air brick again and 150 mm is achieved in all but a couple of small bits where a fall is needed and it would be too much rework to lower the entire thing. I'm mostly happy with this and is probably the best realistic resolution. All a learning curve, thanks all for your advice.

 

[Notch7]

We've managed to get the level down so it's now below the air brick again and 150 mm is achieved in all but a couple of small bits where a fall is needed and it would be too much rework to lower the entire thing. I'm mostly happy with this and is probably the best realistic resolution. All a learning curve, thanks all for your advice.

150mm is a somewhat arbitrary figure -its based as far as I can tell on the likely height of rainsplash -if you look sheds etc next to muddy paths etc, 150mm is around the height the majority of rainsplash reaches

even if the brickwork gets a bit wet above DPC, its a cavity construction so internal skin should still be dry

 

[TullioK]

Yeah I agree it's somewhat arbitrary and I'm not particularly concerned about damp bridging the cavity and coming inside. Nonetheless it doesn't meet the regs and could appear on a homebuyer's report and put someone off.