concrete (laing) ext - new garage and garden room(habitable)

[glerwill]

Hi,
we have recently moved into a concrete house in Bristol - the laing type is a bit like a 'normal' cavity wall house but both leaves are concrete that is poured in situ - no real problems with the house revealed by mortgage valuation or full survey - just a bit wonky here and there!

The house is a large end of terrace with a pitched (tiled roof). There is a very amateur built garage at the side and outhouses behind including a functioning WC.

I would like to knock down the existing garage and put a flat roof garage the full length of the side of the house. At a later stage, I would like to knock down the outhouses and put a flat roof 'garden room' there, possibly with a small shower/wc.

My questions are:

-the gas and the electric connections are under the stairs and lead out to the side of the house - can you build over them and what precautions should be taken or do they need relocation?

-same question about waste water (foul) from the upstairs bathroom?

-does this sort of house have a damp proof course (nothing visible) and how would you connect the DPC of the new garage to it?

-There is a manhole cover to the rear of the existing garage/before the outhouses - how would you deal with this?

I would welcome any input on these points.

Thanks

Graham

 

[noseall]

the gas and the electric connections are under the stairs and lead out to the side of the house - can you build over them and what precautions should be taken or do they need relocation?

You can build over all services except gas, this will need relocating.

Any pipes or services passing through concrete should be sleeved.

-

same question about waste water (foul) from the upstairs bathroom?

The waste pipes will need to find their way into a trapped gully or bossed into a stack pipe.

does this sort of house have a damp proof course (nothing visible) and how would you connect the DPC of the new garage to it?

No need to connect. Just ensure that your new dpm and dpc are fitted at the correct height relevant to ground levels and/or existing house floor levels where pertinent.

There is a manhole cover to the rear of the existing garage/before the outhouses - how would you deal with this?

You can either build over it ensuring that you bring the inspection chamber complete with a screw-down air tight lid into the proposed extension or move it.

 

[maltaron]

I would be very careful to ensure that the manhole, and the drains through it, is for your private drains. If it is a public sewer in South West Water area you may have major problems, they are the most dogmatic and unbending company I have ever come across.

 

[glerwill]

have looked in the 2 manholes - the first one has drains from our upstairs WC our outhouse WC and the same again from our neighbours. The second manhole right next to it is a length of straight open pipe. the drain continues above and below our property.

 

[noseall]

have looked in the 2 manholes - the first one has drains from our upstairs WC our outhouse WC and the same again from our neighbours. The second manhole right next to it is a length of straight open pipe. the drain continues above and below our property.

If the drain is shared (sewer) then you may have difficulty re-locating but not impossible.

However you need to take a great deal of notice of this....

would be very careful to ensure that the manhole, and the drains through it, is for your private drains. If it is a public sewer in South West Water area you may have major problems, they are the most dogmatic and unbending company I have ever come across.

 

[glerwill]

Sorry to pull this old topic back - I am still unsure about DPC in existing house and how to join to DPC in garage base, and I am planning to do the work this week.

The existing situation is:

-Side of house
-concrete path next to side of house below house DPC
-RAISED existing 'two strips' driveway above the level of house DPC

Current plans are:

-FILL in most or all of where the pathway is to raise it to the level of the driveway (having dug down and out trench fill under it)
- either leave a gap so it does not bridge the house DPC or somehow join the DPM of the garage base to the DPC of the house

I am looking for advice on how to do it?

-Liquid DPC - no gap?
- cut into side of house at DPC level and join it? How?
-Use extra DPM in some way?

I have tried to draw it below( may not come out right)....

H I
o I
u I
s I
e I
----- ---------------------------------------------------
I I Drive
I I
I I
-----------------------------
Path

rgds

Graham