The Brew Cabin

Posted: **Tue Mar 15, 2005 4:30 pm**

Hi - I'm after a little advice on how (and indeed if) to proceed with a small difference of opinion between myself and the contractor who has just block paved my new drive. He's done a sterling job with the vast majority of the drive, but has bridged the DPC with a step up to the back door. This step is around 4' wide, and the top is about 1" above the DPC for its entire width. The rearmost brick is not actually in contact with the wall - there is a couple of millimetres gap which as far as I can see is largely filled with sand. Your excellent page on DPC and steps would seem to indicate that this would be OK for a hollow step, but not for a solid block-paved one.

The contractor is adamant that this isn't a problem, they do it all the time and certainly doesn't intend to do anything about it. I have at least managed to extract (the promise of!) a letter stating that they are aware of the DPC bridge and will take full responsibility for any adverse effects it may have - this in addition to their standard 10 year guarantee.

Am I being unreasonable in asking them to rectify matters? Is this indeed an acceptable practice? I am no expert in these matters (as was pointed out to me by their managing director...) and so my reaction is sadly limited to 'DPC bridge = bad'! If the worst comes to the worst, is there anything that I can do as an enthusiastic but time- and skill-limited amateur to ameliorate the DPC bridge - or, as they are guaranteeing the work anyway, would I be best to leave well alone?

Apologies for all the questions - all and any replies much appreciated!

Posted: **Tue Mar 15, 2005 5:11 pm**

Steps can come up to the DPC level - this is now part of Document M of the Building Regs for Accessibility - but the level should not be higher than DPC.

There are ways and means of dealing with the DPC at thresholds (yet another page that is still "in production") but the key point is to stay at, and preferably slightly below, DPC level.

Given your step is only 1200mm wide, it's unlikely to be a major problem, but even so: why not keep the tread level down by 25mm or whatever it is so that there's a much lesser risk?

If they're members of a certain 'Approved Contractor' list, (I'm guessing they may be because of the 10 yr guarantee farce) get them to provide a written statement from the scheme's backers that they (the backers) are happy to provide warranty on paving that is above dpc level. Getting a statement from the contractor is worthless because it won't be them that's held liable should things go awry.

Posted: **Wed Mar 16, 2005 8:13 pm**

You're quite right, they are indeed on a certain approved contractors list. Thanks for the tip - I shall see if we can get anything out of the trade association.

Posted: **Mon Mar 21, 2005 10:17 pm**

I often see this issue concerning the height of the paving and the DPC and feel frustrated that many people including contractors do not seem to undersatnd where this 150mm ideal comes from. This height is deemed to be high enough to stop rain hitting the ground/paving and splashing above the DPC and so saturating the wall. However although an ideal it is not that important if you have a cavity wall construction, as this type of construction allows the external skin of the cavity (often brickwork) to become saturated without the dampness getting across the cavity and into the building. So if you have a cavity wall I would agree with the contractor that you will almost certainly not have a problem (unless the cavity is filled with droppings but thats another story)

Posted: **Tue Mar 22, 2005 2:01 pm**

The problem arises when ...

1 - a damp problem materialises and your buildings insurance company sends out a surveyor who then notices you've had a patio/path/driveway installed that breaches the "Min 150mm below DPC" rule of thumb. They can, and have in the past, refused to settle claims in such situations as the work does not meet generally accepted construction standards.

2 - you come to sell the property. The would-be buyer's surveyor spots the fact that the paving is, relatively, high to the DPC, and so requires either remedial work to correct the problem (at your expense) or a reduction in the asking price to cover the cost of the buyer bringing in a contractor to correct the problem, assuming the mortgage company are willing to issue funds on a property that doesn't meet generally accepted construction standards.

There are all sorts of arguments about the "150mm below" rule, and most of these have been going on for at least 40 years. It doesn't matter who's right and who's wrong; whether splashback is a genuine problem or not; whether minor breaches can be ignored of whether there should be a hard-and-fast interpretation. What does matter is that, at this point in time, it is the accepted wisdom, and it is deemed to be bad practice to breach the rule. For this reason alone, it ill behoves any contractor to mess about with the rule unless there are very good reasons for so doing.

The Brew Cabin

Steps and the dpc (again!)