water coming under deck


Old 10-12-18, 09:06 PM
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Water coming under deck

I have a 10 x 14 deck, watertight surface over a poured slab. Garden touches it on East side and rain comes in through a drain hole. The slab and the deck top both slope away from the house and the garden and yard slop towards the deck wall. No gutter on the deck.

Water is also seeping through one of the cinder blocks (not the one with moss on it from the outside) and I'm wondering how that is happening.

Walls are T1-11 and very slightly damp. Needs cleaned and painted on outside which I'll do next spring.

South wall window allows sun in which helps dry out the slab. I do want to keep it dry.

Right now I plan to clean off the moss, build up the garden where it meets the wall and slope it back and plant some ferns. In a month a gutter will put on the side of the deck that most of the water comes off.

Should I cover up the drain hole? or put some stones around the opening before I put dirt over it?

Any other thoughts or suggestions?



here's another picture. Any thoughts on plugging the drain hole? I'd like to here your reasoning, trying to understand it all.... thanks,

Thanks Marq1. Gutter coming in a month....

back deck (10 x 14) has solid top and walls on most parts, deck is over poured slab. both the deck and slab slope away from house. in the pacific NW - lot's of rain.

back yard and garden bed slope towards the deck / house. drain hole is present to allow any water that might get onto the floor to drain out into garden. over time the garden had been built up and water now flows in via the drain hole onto the slab.

I want to focus on directing the water from the deck top somewhere. If I put a gutter on the side that drips the water I'm not sure how to direct the water away using a downspout as most of the yard is up hill and I don't want to direct it towards the house. I've seen pictures of "dry wells" but this looks like a huge amount of work...

It's also been suggested that I dig a trench under the drip edge, next to the foundation and fill it with stone (I'm assuming one would use some kind of fabric to keep the dirt out) to allow the water to drain down. seems this would require it to be just next to the wall / foundation of the slab in order to catch the water. not sure if that is a good idea - but that is where all the water is going now.

I plan to put more plants in the garden to minimize water coming from that direction.

Ideas? Suggestions?

Thanks very much!
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Last edited by XSleeper; 10-21-18 at 10:45 AM.
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Old 10-12-18, 09:10 PM
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Need a picture from farther back that shows the whole building. First guess is that the siding doesn't overlap the block enough.
Old 10-13-18, 02:53 AM
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Probably run off from the deck, down the back wall and pooling on the ground and weeping into the block. Blocks look wet.

Removing the water from the deck via a gutter would be a good first step. Just building up the dirt isnt going to do much, it's still going to get soaked, diverting water away is needed!
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