Footings question.

tom1ie

Hi all,

builder poured the concrete in the footings for my extension on Friday.

The footings extend out over a clay common pipe for foul water and a concrete common pipe for rainwater. The pipes run parallel with our existing back wall.

There is steel rebar cage in the footings however as far as I know (I wasn’t there for the pour) there were no lintels installed over the area where the footings cross these pipes. (The footings cross the pipe at two separate locations, as the footings are a box out from the back wall)

Is this an issue or is the concrete pour with steel rebar good enough to spread the weight of the roof and walls/ glass French doors, and not transfer onto the pipes below the footings?

We had spoke to a few builders and I know I had said to them all about a pipe(s) being there at the initial meetings. A couple of the builders had said they’d span the pipes with lintels as did this builder but he said you could do it either or.

What do you guys think?

tom1ie

https://www.boards.ie/discussion/2058325542/footings-question

Also I should add the clay and concrete pipe have not been exposed and are approximately 800mm deep from original ground level.

I don’t know how deep the builder has dug the foundation or how much concrete he has poured.

Rows Grower

You're putting a lot of trust in a stranger.

tom1ie

https://www.boards.ie/discussion/comment/121450878#Comment_121450878

? Ok. He’s a builder.

What am I supposed to do go on holiday with him?

tom1ie

Actually I found this:

https://assets.gov.ie/100231/301f205c-c8dd-40d6-8baf-8d5826a51b8a.pdf

and from that:

“1.7.1 Special protection- settlement

1.7.1.1 A drain may run under a building if at least 100mm of granular or other flexible filling is provided round the pipe”

So the pipes weren’t actually exposed and are encased in the original ground.

Mellor

Lintels would be used to span pipes passing through a rising. Not much point in using them to span a pipe if the lintel has nothing to bear on.

The footing is essentially one big lintel spanning the pipes. This is ok, if the pipes are sufficiently below the footing, and surrounded by granular fill (as above). If they were not exposed, sounds like the fill didn't happen.

The pipes are only 800mm deep, I'd have expect the footings and hardcore to go deeper. Unless the engineer has detail something very specific.

tom1ie

https://www.boards.ie/discussion/comment/121451288#Comment_121451288

Hi mellor. The footings for the new single storey extension are actually lower than the house foundation which is less than 600mm deep.

The house is built on hard shale and is a 1962 build house.

The builder has dug the new footings deeper than the existing house foundation.

sydthebeat

Be very aware that any works which are carried out over shared drainage require permission from Irish Water BEFORE you start

water services act 2007

104.—

(1) A person shall not, except with the consent of a relevant

water services authority and following an application for the purposes of this section to that authority, erect or commence to erect,

or cause to be so erected, any structure—

(a) over, or

(b) so close to as to cause a risk to, or interfere with, the structural integrity of or access to,a sewer, drain, water main, distribution system, service connection or related accessories which are owned, controlled or used by another person.

(2) The obligation in subsection (1) shall apply notwithstanding

any provision in any other enactment in relation to control of

development, building standards or practices, or any related

exemptions.

Mellor

https://www.boards.ie/discussion/comment/121451421#Comment_121451421

How is the pipe 800 deep if there is rock at 600mm? Is it in a trench? That’s a positive for you.

https://www.boards.ie/discussion/comment/121452240#Comment_121452240

Good catch. I missed that it was shared drainage.

Gumbo

Sounds like your builder is running the show.

Who is acting as designer and Certifier? Who have you engaged to protect your interests?

What has this person said about the way the contractor has proceeded?

Technical Guidance Document Part H needs careful consideration here and sounds like the builder may have just plowed through with the easiest route and not the compliant route

tom1ie

Hi gumbo- so the design is from a previous design and build company that we were going to get to do the extension but we went with a different builder instead who is going off these plans.

The architect who works with the original D+B company is certifying the extension- he is free lance so has no permanent ties with the D+B company.

The architect has visited site and is happy with the setup and we are sending constant photos over to him.

Obviously the size of the extension 3.9 wide x 5m (19.5m2) internal measurement, has been sized to stay under the 40m2 exemption, when you take into account the garage being converted into a habitable space, the architect is certing this also.

One question I have to run by the architect (again he is happy with the design obviously) is the builder is putting a pitched roof on the extension as per design- I just want to make sure we can have velux windows on both pitches of the roof- (east side and west side) one pitch is on my boundry (tight to the boundry wall) of my neighbour.

I have asked the CC about this and they have directed me to their website but I can’t really find anything on it.