Large hole in concrete floor under sink unit, advice please

[john stafford]

I'm renovating the kitchen of my 1960's detached bungalow, I removed the old sink unit and found a large 12"x18" hole, 18" deep, where water supply pipe enters, see attached pic.
It was filled with mica insulation granules, slightly damp, and musty smelling.

I have removed all the mica granules, now I can see that at the bottom of the hole the pipe (15mm copper) goes into rough concrete, and it looks like it is starting to curve towards the outside wall at that point which makes sense.

I have several questions:

1. is it normal for such a large hole for one 15mm pipe entry ?

2. I can see the damp course in the side wall, it's about 1" below level of floor, but can't see any damp course in the edges of the floor exposed at the hole, although at one side top 1" of concrete has broken away, so I wonder if this is where damp course is. If a 1960's concrete floor has a damp course, at what depth will it be ? and of what type.

3. The old sink unit was supported by a plank at edge of hole, I would like to fill / cover the hole, before fitting new units, the question is how ?
I have thought of first fitting foam pipe insulation to the pipe, the refilling the hole to within 4" from top with sand or gravel, then filling with expanding foam to seal it, and topping with floorboard or external plywood.

thanks

 

[ivixor]

Very curious and unusual. Also unusual to see copper for underground supply. That pipe will corrode and leak at some point I am sure, being in contact with concrete and soil. If it were my house i'd want to to dig down outside, and replace that copper with a length of MDPE pipe. Then fill with concrete to DPC level, then reinstate the DPC then screed/concrete to floor level.

 

[Dereekoo]

Unusual?? What do you think was used between lead becoming a no no and MDPE coming into play

 

[tomfe]

Alkathene
There will be cast iron before you get to the copper pipe, the copper will last much longer than iron.
I would not worry about the copper pipe, i've still see it and it's still going strong. The copper pipe back then was nice and thick.

 

[john stafford]

I dont really want to replace the pipe, so without changing the pipe, how should I fill the hole ?
Obviously I need to consider that at some point in the future the pipe may need replacing, so I cant fill with 18" of concrete.

 

[endecotp]

how should I fill the hole ?

Mica granules? (By which I think you mean vermiculite.)

Or if you’ve thrown that away, polystyrene beads? But beware, they aren’t as innert as vermiculite; keep them away from electrical cables or anything plastic.

 

[Notch7]

Stuff a bit of Celetex in it and forget.....

 

[JBR]

How about using that space for a hidden safe? Bolted to the wall, of course.
You could just place a removable sheet of something on top of the space to hide it.

 

[HERTS P&D]

How about using that space for a hidden safe? Bolted to the wall, of course.
You could just place a removable sheet of something on top of the space to hide it.

And if that pipe ever leaked then it would fill the safe with water.

Andy

 

[JBR]

And if that pipe ever leaked then it would fill the safe with water.

Andy

And then the house! Replace or reroute the pipe.

 

[HERTS P&D]

A small leak would go unnoticed for a long time but would fill the safe with water. Once the leak was noticed then a plumber would be called to fix.

Andy

 

[garyo]

And if that pipe ever leaked then it would fill the safe with water.

Andy

Even better... A fireproof safe!

 

[JP_]

with a hygrometer, or maybe hydrometer ...

 

[Nige F]

I have several questions:

1. is it normal for such a large hole for one 15mm pipe entry ?



thanks

Yes, I've got one in my 60's bungalow copper pipe too. And I put a couple of mains in - 1970's . Soft copper (table y?) It'll see me out.

 

[Ian H]

Mine was 15mm copper too, 1956 semi.