Anyone any insights on the wall foundations in a 1930's mass concrete built Co Co house

Calahonda52 · 16-10-2023 7:45am #1

Took up the laminate floor and this is whats underneath: looks like a layer of bitumen on top of what sounds like a soft floor when you drop the crowbar on it, no bounce.

[The hallway has some sort of screed, crowbar bounces off it.]

The corner shown is damp so plan to take out a 3"core, hence my question, how far in should I keep to avoid the foundations

Floor is coming out anyway for UFH

Thanks as always

Calahonda52 · 17-10-2023 1:17pm

Keep the suggestions coming!😂

Drilled a few holes last night, its about 3" thick and very soft, bitumen layer, its like cinder

Subfloor had settled a bit

Meet topsoil at about 500mm down but no sign of any foundations, or anything solid, up to a meter below floor level, right next to the wall on both sides

lmk123 · 19-10-2023 11:46am

I have a 30’s mass concrete house too, the floor had the very same layer as that, the foundations on my house are about 50mm wider than the walls on each side and between 300-600mm deep. Why do you need to take a core if you’re taking out the floor anyway

Calahonda52 · 20-10-2023 7:44am

https://www.boards.ie/discussion/comment/121258527#Comment_121258527

Thanks for your response, much appreciated.

So just checking, 50 mm wider?

Was looking for the gold bullion so didn't want to drill into the chest!

Easier to see whats going on with the core

10-10-20 · 20-10-2023 7:55am

Yeah, that does look like cinder or slag. What was the local heavy-industry which was generating that waste?

Walls are hardly on the topsoil alone? Any signs of movement in the walls?

Calahonda52 · 20-10-2023 8:37am

https://www.boards.ie/discussion/comment/121261682#Comment_121261682

There is not a hairline crack in the structure.

Possible feedstock for the material? 10 kms away

https://en.wikipedia.org/wiki/Silvermines

lmk123 · 20-10-2023 8:42am

Yeah, the external walls are approx 400mm wide and the foundations are 500mm max, there isn’t a crack in the house, I’d say it’s bomb proof, it’s a mystery to me where that layer of stuff in the floor came from, never seen it before or since, they had around 400mm of big stones under the floor too which I found out since were drawn from a quarry 5 miles away with a donkey and cart, they were some men back then.