Water under floorboards

[Thewedge55]

We have a 3.5ft drop under our floorboards in the kitchen - we have noticed that we get approx 4inches of water when there is rain - I am pretty sure this is the high water table (I have dug a pit in the garden and the water accululates in the pit at approx the same depth of the water under the house.

Do anyone know any solutions to this problem?

Someone mentioned filling approx 6-7inches with concrete upon a DPM - any one tried this?

Many thanks - I really want to sort this as it can smell after prolonged rainfall due to stagnent water

 

[wavetrain]

how many feet drop is outside ground level from floorboard level?

 

[Thewedge55]

The drop outside is about 8inches to our patio - the drop under the floorboards is about 40inches.

 

[stuart45]

Modern suspended timber floors have 4 inches of concrete as an oversite laid above the highest part of the ground next to the house. If this can't be done the oversite is laid to fall into a drain at the lowest level of the ground.

 

[wavetrain]

The water that collects during rainy times is to be expected if it does not have anywhere to drain to as you have concluded yourself.

You next need to explain to this forum if it is just the kitchen that has low earth levels under floor boards, how old the property is and is the low level as a result of a bodger in the past.

It may help the forum if you posted a diagram with measurements of the substructure beneath your floorboards

 

[Thewedge55]

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• Thewedge55
• 27 Feb 2011
• 1

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This was the best i could do, do it help at all?

 

[stuart45]

If the concrete you put in stays above the water table you will not have a problem. However if the water table was to rise it would sit on top of the concrete. That's why oversite concrete is higher than the ground level now.
A crawl space beneath the floor is like a basement with no protection from groundwater.

 

[Thewedge55]

I would make sure the concrete was laid above the highest water mark by approx 3 - 4 inches.

 

[stuart45]

Good idea. Fill up with hardcore first and see if you can get it to the lounge floor level. Modern floors only need 6 inches min from oversite to the bottom of the joists.

 

[WabbitPoo]

Surely filling with hardcore would just create a floor space full of voids, just like a soakaway....

Much better to drain the water away somehow...?

 

[stuart45]

Hardcore,then 4 inches of concrete for the oversite. That's the normal method for an oversite for a suspended timber floor.
Draining is not easy when the oversite is so low. You can use a sump pump, but with a high water table it will keep filling up. Water will always find it's own level.

 

[Thewedge55]

Once there is a good few weeks of dry weather then the water will be gone, i guess that would be the time to do somthing.