How to stop rain soaking under the shed


Old 11-11-14, 12:11 PM
Thread Starter
Join Date: Nov 2014
Location: Canada
Posts: 1
Received 0 Votes on 0 Posts
How to stop rain soaking under the shed

Hi folks,

I have a shed build set on a concrete foundations. The foundation is slightly larger than the shed footprint. Here's the problem... There is a small gap between the shed wall and foundation as you can see in this photo:

Name:  Shed Wall - Where the rain gets in.jpg
Views: 23735
Size:  38.3 KB

When it rains, water is getting onto the foundation and between the gap and touches the woodchip panel which lines the inside of the shed. The woodchip soaking up the water like a sponge and is starting to rot a few inches from the bottom (and I even noticed a small mushroom growing on the wood today - not good!).

Here's a photo of the worst bit on the inside of the shed:

Name:  Shed - Inside - wet chipboard 1.jpg
Views: 25066
Size:  28.7 KB

I have two questions:

1) What is the best way to stop the water coming in?

- Is there a way to close off and waterproof the gap?

- There is no guttering on the roof and the water is splashing on the stones and back onto the foundations. I'm guessing guttering would help immensely?

2) How should I treat the wet woodchip (it has no preserve on it)?

- is there something I can put on it that will stop the rot and protect it? (so I don't have to cut it out and replace it which will be a challenge I think?)

- As it is the internal "wall" should I still treat the wood above incase it continues to soak up the water?

Many thanks!
Sponsored Links
Old 11-12-14, 10:34 AM
Join Date: Nov 2007
Location: MI
Posts: 2,634
Received 1 Vote on 1 Post
It's hard to tell from the over-exposed close-up picture what you have going on there. In general:
The bottom plate should be pressure treated.
It should be set on a layer of foam sill plate insulation.
The sheathing should never go all the way to the ground.
It's wise to use a 6" band of PVC trim board around the base, then the sheathing sits on the top edge, and then the siding over all--stopping about 4-5" from the ground . When rain splashes it won't reach the wood siding. Plus critters are less likely to gnaw through plastic than wood.
Old 11-12-14, 01:40 PM
Forum Topic Moderator
Join Date: Mar 2005
Location: USA - N.E.Tn
Posts: 47,690
Received 330 Votes on 293 Posts
Ideally you'd have flashing under the bottom board extending out to the end of the slab. A good bead of caulk along the outside bottom edge would be better than nothing.
Old 11-12-14, 03:31 PM
Banned. Rule And/Or Policy Violation
Join Date: Apr 2013
Location: USA
Posts: 4,294
Received 0 Votes on 0 Posts
No real great way to fix this without a lot of work.
Slab was pore to low, never should have been pored bigger then the shed.
Never should have need wooden trip cap used between the siding and the trim.
No pressure tread bottom plate.
The only "fix" I see that's going to last is removing that bottom trim, drip cap and bottom 3 pieces of siding. (it can be done with a 12" long bimetal metal cutting blade.
Cut out the old OSB, replace with new leaving it 1/2 off the slab.
Add storm and ice shield to the wall.
Add coil stock 6" up the wall and bend it so it runs out over to the edge of the slab and down at least 1" over the edge.
Now add 1 X 6 vinyl lumber, Z moulding, kick out strip then reinstall the siding using stainless steel siding nails in the face of the siding.
That would be the right way, but we all know that's not going to get done.
Silicone caulking's just going to act as a dam when it fails.
Old 11-18-14, 11:37 AM
Join Date: Nov 2014
Location: US
Posts: 8
Received 0 Votes on 0 Posts
Looks like a tough job to me.
Just put this tent over your shed to protect it!
Name:  P3150028.jpg
Views: 18566
Size:  41.1 KB

They´re also offering storage tents if you have to demolish your shed!

Dont be mad at me but seriously i agree with joecaption. Thinking its the only chance to make your shed last.
If you post a photo of the whole shed who knows maybe someone could help.
Old 11-19-14, 09:14 AM
Join Date: Dec 2008
Posts: 7
Received 0 Votes on 0 Posts
Well the question is "where is the water" coming from? You need to answer that before you can solve your problem. Looking at your photos, I would say "MY HUNCH" is a bulk of the water is coming up off the ground surface onto the concrete pad because it looks too low. If that is in fact the problem...and that's a BIG IF. What you need to do is dig a small trench around the side of the pad, form it and pour a concrete "curb" around the perimeter of the pad that is up 5 or so inches on the shed side sloping down.

In addition, I would think you could get some caulking that goes around pools and pump some around the shed itself. You thin put sand on top of the caulking to get it to dry and it helps make it last longer too IMHO. However, the caulk will only keep water coming off the shed roof from seeping back in and you probably could put a small gutter system on the shed too if that is where the water is coming from.

Another thing you could do is "jack the whole shed up" and put some pressure treated runners up under there, then lower the shed back down, and then go inside and drill some huge screws into the runners. However, if the grade and depth of the pad is wrong, you really still need to solve that problem IMHO. Having pressure treated runners sitting in water 24x7 will seep out all the poison eventually and the critters will eventually start munching on it prematurely

Also you can buy the arsenic and paint it onto doesn't work as well as pressure treating which forces the poison deep and far into the pores of the wood. I'm not suggesting that here because its a worse idea that the other stop gaps but just letting you know.
Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Thread Tools
Search this Thread
Ask a Question
Question Title:
Your question will be posted in: