Extension - who surveys the drains?

[littlebearsmummy]

Possibly the most boring question ever posted!

We have submitted plans for a 2 storey extension which will include extra bathrooms and moving the kitchen.

Our architect has not done any kind of survey on the house or garden (he's literally just drawn the ext plans) and to be honest it never crossed our mind to ask. A friend has just told me she has a dispute between her architect and her builders, over who's responsibility it was to survey and plan where the new drains should go.

Any views on who should do this? Clearly we will ask the architect and as we haven't started getting builders quotes in, we have time. I'd just like to be a little more aware of who typically does this.

Thanks

when we had our architect draw our plans he checked for draimnage as we needed to see who/if our drains were shared with. He then got our water supplier to come and do a free site inspection which was free. A builder will only be following the drawings he is provided with so the info should be shown on these.

Can I be nosey and ask did the architect provide plans with all wall measurements on etc?

Ours has told us builders don't need these anymore as a scale will be sufficient. We are pushing him for them however, though he's taking forever to come back.

It sounds like you are at the Planning Permission stage. Planning Officers are not specifically interested in drainage specifics, but I would expect the location of rainwater and soil pipes to be on your plans.
Once you get planning approval, your architect should submit detailed plans for Building Warrant approval. These should show how your new WC especially ties into your existing drains.
Our plans do not have detailed room measurements on them, which I'm a bit hmmm? about as I want to be able to use exact room sizes in my online 3d planning tools!

Ours did have exact measurements on and were also to scale. Our builder misread the measurements and pug extrnsion is 30cm too long as a result! A planning officer came and measured it and told us off but said we could apply retrospectively for permission of just wait four years.

You need to talk to your water company about the drains. They may want a video of the pipe work. Then they'll give you permission to build over them or move them etc.

Our builder decided where to move our manhole to but we had to get permission from the water comp at first. The architect just did our drawings and building regs package. We didn't need planning permission.

Hi, some measurements were shown ie the main shell but our utility that is getting split into a utility and wc does not

Make sure you get a 'build over' agreement if you need one! We have just forked out over £500 for an indemnity policy to cover the lack of one of these, even though we didn't build the stupid extension...

Do you have reason to believe you are building over drains? i.e is the extension going to be where there is a manhole cover?

I think you need to be thinking of drainage if you are building over drains -it can add significantly to the cost. If the drains are main drains i.e public then you need water company permission for a "build over agreement" if within 3 metres. This can be very time consuming and expensive. A friend has cancelled their extn and will move due to this reason.

An architect does tend to build plans to scale without drainage details etc but I would expect yours to advise, from experience, on other aspects, like drainage, that could impact the build.When you bought the house you will have had the water survey details or you could ask the water company for copy of the plans. If the house is old then exact plans maybe challenging as not everything was recorded.

Once planning has been achieved then you will need building regulations which are the detail of how it should be built - often referred to as builders drawings. Your architect can do these and should have quoted for it. You could use a separate company however.

Having just got planning permission for our extension we are now having to fork out the princely sum of £340 to the water company for a 'build over drain' permission. What is more annoying is that even if they refuse we have to pay this fee and they give you no time guarantee for responding.

Our architect is managing all of this prior to us awarding the contract to a builder.

I think the short answer has to be "the person who draws the plans"

Everyone else is entitled to believe the plans are correct, and to follow them, and to charge extra for changes or delays.

BCO will (should) inspect the drains before they are covered up, and must be notified when they are ready.