Crawler hole

pippo · 17 Nov 2008

Hi all,

In our 1930s ex authority home, there is a crawler hole under the floor between the sitting room and the hall which over time has been opened up too far. there are joists running over it however they are not supported properly and the floor is sagging. The hole does provide good access (its aboout 3ft high, the hole about 3/4m) but it needs fixing.

What is the best way to get the floor back up where it should be (around 10mm) and keep it supported and still keep some access. Is there maybe some kind of jack or support that i can place with timber on top and permanently jack it up?

Any ideas would be great.

Thanks

Pippo

gday2uk · 17 Nov 2008

Wedge some 4 x 2 timber between the joists and a concrete block on the sub floor. This isn't permanent and would need replacing in a few years after movement etc. To make it permanent you could jack it up and build some block piers spanning a piece of say 6 x 2 timber to take the weight.

pippo · 17 Nov 2008

Best make it permanent. Ill go with the second one.

Thanks gday2uk

pippo · 21 Nov 2008

Ok I thought I would post a picture up of the crawler hole which is causing the floor to drop 10mm just to make sure that the above suggestions are the best way to sort this. 4 joists are being supported by some pretty thin timber. I need to jack it up 10mm then support it permanently to even up the floor. Any further ideas?

Steve · 21 Nov 2008

I'm guessing you need to keep this access point?

Does the wall continue above at this point? Or does it finish at the joists?

If there is nothing else to support above, I'd knock out the brickwork remaining at the top, its not stable. Also knock out the two whole bricks we can see at the left and right. Go and buy a substantial piece of timber, jack up the joists, and insert piece of timber where you have removed the bricks. A concrete lintel might do the job, not sure. You may also have to make good a few missing bricks below - the hole isn't exactly straight

Disclaimer: I'm not a builder.

gday2uk · 21 Nov 2008

Support joists either side of hole, remove upper brickwork and insert prestressed concrete lintel, long enough to have a good 100mm bearing on each side of brick. After installed jack that up to the levels you require and then pack out any gaps between the lintel and side bearing bricks with pieces of brick or slate, cement up and leave supported while it dries. Doing this means you could widen your hole (!) and give you more room to manoeuvre.

pippo · 21 Nov 2008

Future access would be required yes. Above this wall is a doorway, this side of the wall is the sitting room, and the other side of the wall is the hallway. So the floorboards above this wall obviously run left to right over the top of these joists as we look at it. Here is a better picture.

Steve · 21 Nov 2008

I'm probably talking gibberish here, but where would the damp course have been in this wall? Would there have been one?

pippo · 21 Nov 2008

The damp proof course is old tar type and runs along the top of the bricks which are hangin by a thread (just visable in the pics) so idealy I would want to keep them in and prop them up.

Steve · 21 Nov 2008

Put a new DPC into whatever you replace them with. Those bricks aren't going to do you any favours by keeping them.

pippo · 21 Nov 2008

gday2uk

What type of jacks will I require for this? can i rent them? The joists are 10 courses above ground.

pippo

JohnD · 21 Nov 2008

If it was me, I would cut a few lengths of timber as supports, insert them slanting, then tap them upright with a hammer. As they come upright they will lift what's above.

p.s. I really like your crawl space.

pippo · 21 Nov 2008

hmm options options. Never been complimented on my crawl space before lol.

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Crawler hole

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