Wet clay and clay heaving in crawl space

[vbhardwaj87]

Hi! We have recently purchased a 1930s built house in Greater Manchester. There are a lot of issues that we are discovering after the purchase. Damp and condensation are the usual culprits.

Recently we found out that there is wet clay in the crawl space under the dining room. And it seems there is clay heaving also happening around the same area.

Is this common? Is this ok to ignore? What should we do?

 

[Ihavenojob]

Do you have a river or stream near to you?

 

[JohnD]

Do you have any pipes or drains in your house that contain water?

(Yes you do)

Much more common than streams.

Yours are old enough to be leaking.

Have your neighbours had similar?

Please photograph the airbricks round the house, showing how far above ground level they are, and the drains, gullies and manholes.

Do you have a water meter?

 

[jacko555]

Does it get wetter after a bath

 

[martygturner]

Its cyclic swelling, those cracks appear after multiple cycles of the clay expanding and contracting, probably over years as the clay plates are large.

I would check the water table, dig a hole and see how far down you get before it fills with water and also check for blocked gutters, soakaways or broken drains.

 

[vbhardwaj87]

Do you have a river or stream near to you?

No river or stream nearby. We are on a slope though - in the middle of a downward slope.

 

[vbhardwaj87]

Does it get wetter after a bath

Its cyclic swelling, those cracks appear after multiple cycles of the clay expanding and contracting, probably over years as the clay plates are large.

I would check the water table, dig a hole and see how far down you get before it fills with water and also check for blocked gutters, soakaways or broken drains.

We will definitely check for water table. But assuming that this, in fact, is a water table problem, what solution can we look at? Is this common?

 

[vbhardwaj87]

Does it get wetter after a bath

So this is not near the bathroom area and we haven’t yet checked if this gets particularly wet after bath. But yes this does seem to get worse after / during rainy season

 

[vbhardwaj87]

Do you have any pipes or drains in your house that contain water?

(Yes you do)

Much more common than streams.

Yours are old enough to be leaking.

Have your neighbours had similar?

Please photograph the airbricks round the house, showing how far above ground level they are, and the drains, gullies and manholes.

Do you have a water meter?

Here are some additional pics that show how far above the clay are the airbricks. We have checked for leaks from the drains and pipes already. Engineers said there was no leak related problems.

We checked with the neighbours also. None of them seem to be facing issues as severe as ours.

 

[conny]

Possible it's surface water running down the slope and, as it's a clay base, it won't filter into the ground as easily if it were permeable soil.
Get friendly with a few neighbours and ask if they know what theirs are like. If theirs are similar I wouldn't worry too much.
Still carry out the checks that others have suggested, if only to put your mind more at ease. After all, the house has been standing for 90 years already.
Sorry, you posted as I was typing.

 

[vbhardwaj87]

Its cyclic swelling, those cracks appear after multiple cycles of the clay expanding and contracting, probably over years as the clay plates are large.

I would check the water table, dig a hole and see how far down you get before it fills with water and also check for blocked gutters, soakaways or broken drains.

Assuming this is cyclical and has happened on account of years of impact, what can be done to resolve this concern? Should we be worried?

 

[vbhardwaj87]

Possible it's surface water running down the slope and, as it's a clay base, it won't filter into the ground as easily if it were permeable soil.
Get friendly with a few neighbours and ask if they know what theirs are like. If theirs are similar I wouldn't worry too much.
Still carry out the checks that others have suggested, if only to put your mind more at ease. After all, the house has been standing for 90 years already.
Sorry, you posted as I was typing.

This is helpful. Thank u.

We can see earthworms also along with water on the clay. Does this tell us something?

 

[vbhardwaj87]

This is helpful. Thank u.

We can see earthworms also along with water on the clay. Does this tell us something?

Just checked it is a drain worm.

 

[Mottie]

No river or stream nearby. We are on a slope though - in the middle of a downward slope.

I posted this a few years ago.

 

[JohnD]

Just checked it is a drain worm.

Is it red?