Author Topic: DPC Ground Clearance  (Read 10602 times)

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rj1423ah

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DPC Ground Clearance
« on: March 07, 2013, 10:23:04 am »
In my property the rear patio door opens directly over the tiles i.e. there is practically no clearance between the door and the tile. A couple of architects have pointed this out to me and say there should be 150mm clearance from the DPC to the ground.

I checked Part C, section 5.5(b) Building Regulations Part C
and they appear to be correct but I also saw the following clause:
5.6: "The requirement can also be met by following the recommendations of Clauses 4 and 5 of BS 8215:1991, BS 8102:1990"

Does anyone know what these clauses are?
I don't want to raise the issue with them if the alternative method mentioned above does not require the 150mm clearance.

thanks,



Philofacts

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DPC level above ground
« Reply #1 on: March 08, 2013, 09:28:56 am »
You say your "rear patio door opens directly over the tiles"  Do you mean paving slabs or tiles on a roof?

As you have found it is both a Building Regulation and NHBC standard requirement that DPCs are provided in external walls at a minimum 150mm above finished ground level.

However, in order to comply with Part M (Mobility) Building Regulations, the maximum step up from an external door for mobility is 15mm.
As the DPC is level and under your door, in this case it be less than 150mm (at the door only) and the ground level should slope downwards, or the DPC stepped down, either side of the door until the 150mm is achieved.

The 150mm requirement is designed to stop rain splashing up off the ground above the DPC and causing damp by soaking a wall. As your patio door is presumably impervious, this should not matter.

The requirement reference alternative in Part C of the Building Regulations you mention applies to walls subject to ground water pressure and refers to tanking details etc.
Nevertheless the 150mm above finished ground level requirement is still necessary for the external wall DPC in this case.
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rj1423ah

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Re: DPC Ground Clearance
« Reply #2 on: March 09, 2013, 04:50:00 pm »
Phiofacts, thank you for the detailed response and explanation.

The door opens over paving slabs and the garden actually slopes down towards the house so I guess they haven't met the regulations. There is a some single between the wall and slabs either side of the door but it's still above the DPC.

I'll raise the issue with Barratt and take it from there. Thanks again for the advice.

Philofacts

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Re: DPC Ground Clearance
« Reply #3 on: March 11, 2013, 07:04:58 am »
The DPC, if it is level and directly below the door, then the ground either side is too high - even if it is shingle.  This should slope down either side of the door.

No doubt the shingle may help in the prevention if standing water as the ground slopes towards you house (never a good idea without a land drain!)  it will not prevent the DPC being by-passed by rain splashing up from the ground.
This is happening and can be seen by the damp wall well above DPC level to the right of the dustbin.

Barratt need to address this now.
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rj1423ah

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Re: DPC Ground Clearance
« Reply #4 on: May 02, 2013, 04:16:14 pm »

Well, they finally came round to take another look and offered to remove the shingle to make the clearance!
They reckon the wet patch is caused by the water but next to the window.
I'll keep a close eye on it and first sign of damage and I'll have to insist they lower the patio to a suitable level.

Philofacts

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Re: DPC Ground Clearance
« Reply #5 on: May 03, 2013, 08:36:47 am »
Judging by the gap between your posts, Barratt took nearly TWO MONTHS to even come round to "look" at your problem! 
Hardly 5 Stars!

Are you sure that your guttering is not leaking too?
This would explain the wet patch.

The important point is not to give up and keep writing to Barratt if this issue remains unresolved.

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rj1423ah

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Re: DPC Ground Clearance
« Reply #6 on: May 04, 2013, 03:53:45 pm »
Since they left site they just can't be bothered any longer. They came to fix some loose tape seams a couple of months ago and only next week are they coming back to finish the job off!

Thanks for the advise regarding the guttering, I'll keep an eye on it. I'm thinking of moving later in the year so it will be interesting to see what the surveyor makes of it.


Philofacts

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Re: DPC Ground Clearance
« Reply #7 on: May 06, 2013, 09:32:23 am »
Owners of new homes often find that once the site manager and trades have left site, and they are in the hands of the regional office customer care department, the level of service falls or disappears altogether.

It is easy for customer care managers to ask the site manager to attend to any snags than it is for them to actually arrange for the work to be done themselves.
Most are just administrators and have no skills in dealing with the trade sub contractors.

You would be wise to get Barratt to attend to every possible outstanding defect before you put your home on the market.
If you wait for a surveyor to note defects you could lose or delay a sale and may even have to reduce your price
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The Brickkicker

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Re: DPC Ground Clearance
« Reply #8 on: October 24, 2013, 02:05:57 pm »
Despite being an age old problem ....this is issue keeps cropping up.

I have had several clients had to go to arbitration with the NHBC over the problem after I have pointed it out in a report.

If you want a level patio then there are ways to achieve it....the picture above is clearly poor practice
...even with permeable stone.

Some in the industry may argue that we don't have solid walls these days and so there is no need to worry about water getting over the DPC ...as the cavity offers protection.

But they don't tell you about the green algae that develops on constantly wet brickwork
or the frost damage that can occur to permanently saturated bricks.
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Philofacts

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Re: DPC Ground Clearance
« Reply #9 on: October 24, 2013, 02:23:09 pm »
If DPC levels above ground was not critical, it would not be a Building Regulation and NHBC standard.
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