What is the depth of the sub-floor space under properties on the ladder?!

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Permalink Reply by Hugh on June 28, 2010 at 10:02

Where you posted is great.

Not sure if I can be much help since I have a cellar. It may be quite different from one group of houses to another since the Ladder was built up by small builders building from as few as 2 to as many as a few dozen houses.

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Permalink Reply by Salsa on June 28, 2010 at 10:29

Thanks for the reply.

Oh I see. My flat is in a semi detached house build in about 1905.... It is a bit different to other houses on the ladder.

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Permalink Reply by Alison on June 28, 2010 at 11:24

My place has a little cellar but beside that the floor space between the floorboards and foundation is about two foot. But a lot of the houses are different from each other.

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Permalink Reply by andy thomas on June 28, 2010 at 14:18

We had a lot of coal dust, soil and general rubble bridging the slate damp course in parts of our cellar, which caused damp to rise up the walls which led to the lounge floor rotting and eventually collapsing into the cellar by the window bay. All this was dug out to leave the damp course exposed all around the cellar before the floor was repaired and outside, the garden was dug down by the bay window to 6 inches below the damp course, making a feature of the stepped garden at the same time. Since the walls have dried out we have not had any damp problems.

As for the depth below the floors in these houses, it varies a lot but it should be at least 1 foot. It's rare for these Vicwardian houses to have 'site concrete' (a thin layer of concrete on the ground) so if you hit firm compacted clay when you're digging out, you know you've reached the original ground level. Do make sure that nothing lying on the ground touches any part of the wooden floor (except support piers) otherwise damp will seep up into the joists or floorboards. Also make sure there is plenty of ventilation under the floor so that air can flow horizontally under it.

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Permalink Reply by John OAKES on June 30, 2010 at 3:53

Andy Thomas says most of the important things, and 1-3 feet is a normal gap between floor and 'site-concrete'.
The important thing is to make sure that the air-bricks at the front and back of the property are cleared and working so that fresh, drying air circulates under the floor. If there is room, you should also check that the brick piers which (should) support the main floor -joists are still functioning, and that they have a barrier - commonly slate or a piece of damp-course - just under the joists, to prevent damp seeping up the mortar and causing rot/woodworm .

If it's not there, crawl under and insert one -or get someone else to do it.

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Permalink Reply by Salsa on June 30, 2010 at 9:29

Thanks for the advice that is really helpful.

From what I can tell the floor space only seems to go down about 1 foot.

I'm not sure if there are barriers protecting the joists, there could be slate over the brick piers from what I can tell, but I'm not exactly sure what I'm looking for.

I have one air brick at the front of the property but have been advised that I need more.

Could anyone recommend a good person to help me install barriers for the joists if necessary and airbricks?

Many thanks for you help so far!

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Permalink Reply by andy thomas on June 30, 2010 at 14:22

I'm not sure if there are barriers protecting the joists, there could be slate over the brick piers from what I can tell, but I'm not exactly sure what I'm looking for

Look for a sheet of slate between the brick piers and the underside of the joists resting on top - occasionally there may be more than one slate as builders sometimes pack more in to get the floor level.the slate should be a bit wider than the joist so that all of it is supported by the slate and no part of the joist touches the pier below. Occasionally the slate may be embedded in between courses in the brick pier itself.

If the floor has had work done on it - or been replaced- in the last 40 years or so, instead of slate there may be a black plastic damp proof membrane instead. I have seen other things used by bodgers - paint can lids, plastic bags, hardboard, wall tiles, etc but slate and plastic DPM are the only reliable materials you can use here.

Good luck!

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Permalink Reply by RNM on August 10, 2010 at 13:27

Hello

Yes we had a similar issue - our entire kitchen floor was blocked with debris and old coal and dirt. All the joists were rotten through, the brick piers had crumbled and so a previous load of builders had just packed dirt underneath, which was holding up the floor. There was one blocked airbrick and a drain leaking into the foundations.

The depth under the floor was only about a foot or so...we had to refill ours with new joists, new brick piers, a black plastic damp proof membrane, more air bricks etc and this has finally stopped the damp. I think the room next door and under our hall suffer from the same issue but we are ignoring that until we have enough cash to sort it properly.

Our property is a slightly older terrace but it was pretty obvious when we hit the bottom about a foot down. It was all just in terrible condition!

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