Loads of builder's waste under subfloor - is this really common?

[a twig]

I’d suggest finding less “helpful” friends

 

[Lacan07]

Your situation doesn't appear to be as bad as this guy -> https://jack-kelly.com/insulating_our_victorian_living_room
Rotting joists, unsupported load bearing wall, and failed damp proof "treatment".

If you have the entire floor up, use the opportunity to get some insulation under there.

Fair play to that guy, what a lot of work he's put in but why is he insulating the walls with PIR on batons?

 

[Lacan07]

Insulation is the plan.

A friend of mine has just thrown in a comment that I could really do without, which is that I may not want to have all the waste removed as it could cause the external walls to end up acting as small retaining walls. Haven't had a chance to clarify what they mean (and they do have qualifications that makes me pause to think twice about what they've said). There is no talk of excavating anything here, simply removing what's been dumped to reinstate the original. Really confused that this would suggest the waste is having some kind of structural effect now.

I think most people would be confused with that suggestion

 

[info_45]

I need to speak to them but I think it might have been because I described the subfloor as 2 feet deep, so potentially they are imagining 2 feet deep against the base of the external wall. Although in the centre of the room the waste might not be far off 2 feet, thats only against the sleeper walls. Its shallower around the edges, and right by the external back wall I can just about see the bare earth beneath, so much less here. Even if it was deeper, its not compacted or anything its just tipped material, so still struck me as an odd thing to say.

 

[stuart45]

I think most people would be confused with that suggestion

I'm confused if it came from an engineer. Older houses often had crawl spaces of 2 or 3ft below floor level, but the floor was usually a fair bit higher than the external ground level. It needed to be to allow for the air bricks.
The amount of earth being retained was usually only about 12inches or less.
A cavity wall filled with concrete, or a 9inch wall will easily take that, especially with the weight of the house on top.
Foundations in the cellars of houses in the USA sometimes fail through hydrostatic pressure when built with 8inch hollow blocks, but they are retaining a lot more earth.

 

[fernicarry]

Your situation doesn't appear to be as bad as this guy

Most shocking thing about that blog is how cheap materials were in 2010!!

I removed lots of debris from under the floor of the back room. Rotten wood and plaster, lots of bits of linoleum, old electrical bits. No where near as much as you are dealing with but it feels good to know it’s all tidied up and airflow is unrestricted. I also insulated between the joists. All done from below without lifting the floor.

If I ever had a phobia of confined spaces, or heights for that matter, this house has cured me.