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walkereng
walkereng, Consultant
Category: Structural Engineering
Satisfied Customers: 2829
Experience:  Structural Engineer with over 30 years of experience.
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I have a 'gravel drain' at the side of a patio, that was

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I have a 'gravel drain' at the side of a patio, that was installed in 2007 by previous owner. When it rains the cellar gets very damp, seems i think this should not happen. 1906 UK Edwardian Double Skin build
Assistant: Thank you. Can you provide any more details to help us find you the right Expert?
Customer: I want to know if i cn cement over the drain to slope the water away and onto the patio. The patio also has not been grouted between the slabs, I wonder why not ?
Submitted: 1 year ago.
Category: Structural Engineering
Expert:  walkereng replied 1 year ago.

I can help

Expert:  walkereng replied 1 year ago.

Do you have any pictures you can share with me?

There is a button on the Chat Window that lets you attach files.

Expert:  walkereng replied 1 year ago.

I am still here to help if you need it.

Customer: replied 1 year ago.
The images show the 2 external sections of wall that either have a gravel strip or mud strip next to the wall. The internal images are the bottom of those walls. The mud one is the worst culprit is the mud one it gets very wet on the surface and down below.The patio was laid in 2007 and has not been grouted.I suppose I want to to know if I can cement in to the wall, but do not know where the 'damp course is'
Expert:  walkereng replied 1 year ago.

The International Residential Code states:

R401.3 Drainage.

Surface drainage shall be diverted to a storm sewer conveyance or other approved point of collection that does not create a hazard.

Lots shall be graded to drain surface water away from foundation walls. The grade shall fall a minimum of 6 inches (152 mm)within the first 10 feet (3048 mm).

Exception:

Where lot lines, walls, slopes or other physical barriers prohibit 6 inches (152 mm) of fall within 10 feet (3048 mm), drains or swales shall be constructed to ensure drainage away from the structure. Impervious surfaces within 10 feet (3048 mm) of the building foundation shall be sloped a minimum of 2 percent away from the building.

Expert:  walkereng replied 1 year ago.

You most certainly can place a concrete overlay on your patio and slope it to drain away from your house. Just make sure you place a flexible joint sealer in the crack between the new concrete and your foundation wall.

Expert:  walkereng replied 1 year ago.

If you feel you have received a satisfactory answer to your question, click the Rating button that is appropriate. Experts are credited for each adequately Rated answer they provide. If you have additional questions, please let me know. Thanks

Customer: replied 1 year ago.
The patio does have a slope on it towards the garden, there is a soakaway pipe under the step you can see.So I can fill in the gaps between the slabs ? I do not want to lay concrete over it.If I fil in the 'gaps' and use flexible joint sealer, does this have to be below or above a damp course ?Where is the damp course on each wall ? This is my fear, that damp will now go up, rather than down.
Expert:  walkereng replied 1 year ago.

I would fill the gap between the stone patio and the foundation wall with concrete at a more exaggerated slope to make sure no water pools along the wall. You need to provide a premolded joint filler (like you may see on the edges of sidewalks) up against the foundation wall before you pour your concrete. Leave it slightly recessed so that you can seal the joint with flexible sealer.

Another issue I see are all of the joints between your patio stones. All of those joints allow water to freely enter the ground around your home. Those need to be filled with clear, flexible sealer.

Customer: replied 1 year ago.
it looks like the patio job is only half done and the gaps not completed, in the UK we use a sand based mortar to fill in such gaps. Is it obvious where the damp course is from the images ? I guess you are USA person
Expert:  walkereng replied 1 year ago.

Yes I am.

Expert:  walkereng replied 1 year ago.

If you feel you have received a satisfactory answer to your question, click the Rating button that is appropriate. Experts are credited for each adequately Rated answer they provide. If you have additional questions, please let me know. Thanks

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