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How to seal the bottom of shed walls?

jjebw
Building a Reputation

How to seal the bottom of shed walls?

Hello, anyone have any suggestions as to what I could do to seal the bottom of the shed walls? Sand and debris keep coming in and building up. It is a metal shed with a concrete slab, the walls are also staying to rust at the bottom.

 

Community manager's note: Check out How to waterproof a shed floor for expert advice.

 

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MarcinW
Growing in Experience

Re: Seal for shed walls

@MitchellMc  Thank you again for the help and the idea!

Will the method described in the link you’ve shred also work if applied on the inside of shed (I can imagine the outside placement is much better as the water will firstly run off instead of sitting under the bottom edge…)?

 

The challenge I face is that the shed will sit with its two walls (long and short) directly agains the garage wall as the slab will not allow for a gap between. (I attach the photos of the slab and the adjacent walls). 

 

Or is there a different/better method that would work under these circumstances? And do you think I should be paining/sealing the concrete first for a better adhesion/tighter seal?

 

Any idea and experience much appreciated!

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EricL
Bunnings Team Member
Bunnings Team Member

Re: Seal for shed walls

Hello @MarcinW 

 

You are in a unique position to apply the floor seal because the shed has not yet been anchored to the cement slab. I propose thinking about how you can put the Sika 300ml Grey Sikaflex 11FC Plus Polyurethane Adhesive Sealant under the bottom channel and start assembling from there. It's even possible to put the aluminium L channel in as well while the wall is not yet in the way.

 

I don't recommend sealing the floor at this point as the adhesive sealant works better when in direct contact with concrete. You can paint the slab later on when the shed is in place.

 

In regards to the gap between the concrete wall and the shed, I suggest building a small PVC gutter and attaching it to the shed. I recommend using Holman 32mm x 3m Class 12 PVC Pressure Pipes and Kinetic 32mm Galvanised BSP Pipe Saddle Clips - 10 Pack. 

 

In order to build the gutter simply cut the 32mm pipe in half and use the saddle clips to hold it in place. 

 

If you need further assistance, please let us know.

 

Eric

 

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MarcinW
Growing in Experience

Re: Seal for shed walls

Terrific advice @EricL , thank you!

 

You’ve mentioned adding an aluminium L channel. Where would you put it, on the inside of the shed wall and attach with SikaFlex 11FC (ie same way as in the tutorial under link shared by @MitchellMc but on the inside)?

 

Thank you!

MitchellMc
Bunnings Team Member
Bunnings Team Member

Re: Seal for shed walls

Hi @MarcinW,

 

It sounds like @EricL is suggesting that the L angle can be installed before the wall as per the guide. I believe he's mistakenly said channel instead of angle. I'm sure he'll let us know if he is thinking of another channel. However, if you're not confident installing it prior to the wall on the outside, then you could install it on the inside.

 

Please let us know if you have further questions.

 

Mitchell

 

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MarcinW
Growing in Experience

Re: Seal for shed walls

Thank you @MitchellMc !

 

Regarding the installation of an L angle on the outside (between the garage wall and the shed wall), are you recommending to install it:

- on the ground against the wall first, caulk it (or caulk the shed wall) and then press the shed wall against it for the bond?

OR

- install the angle on the shed wall first, then caulk it and push the entire shed (with the angle installed and caulked)  against the garage wall?

 

The challenge I see  is that I don’t know how to ensure the L angle is water tight if it’s on the outside as there’ll be no space between it and the garage wall to put the caulking gun in there to fill all small holes?

 

How would you go about it?

MitchellMc
Bunnings Team Member
Bunnings Team Member

Re: Seal for shed walls

I'd suggest installing the angle on the ground against the garage wall and waiting for the adhesive/sealant to cure @MarcinW. You can then apply a bead of sealant along the bottom of the angle, or the shed wall, and push the wall up against it. The angle is just a secondary measure to ensure the area is sealed. On a new shed build, I feel the most important area to seal is directly under the walls. A nice thick bead of sealant needs to be applied to the concrete and the wall placed on top of it.

 

Mitchell

 

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MarcinW
Growing in Experience

Re: Seal for shed walls

This is a great help. Thank you @MitchellMc and @EricL, I really appreciate it and hope it’ll also help others with similar shed projects. 
It’s amaIng to hear from the experts so quickly and very very helpful! Great community!

I’ll keep you up to date on the outcomes and thank you again. 

MitchellMc
Bunnings Team Member
Bunnings Team Member

Re: Seal for shed walls

Do keep us updated, @MarcinW. I'll be looking forward to hearing how it went.

 

Reach out anytime you need assistance; we're here to help.

 

Mitchell

 

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Sath
Growing in Experience

Re: Seal for shed walls

Moved into a house with a shed which had some concrete put in earlier to seal the shed base. I had water coming through and i put sealant inside and has stopped a lot of water coming in . But I can see water getting collected within the corrugated gaps. See attached pics. Should i remove the concrete covering and put in sealant or is there another way ? Worth putting in more drainage around? I am thinking is it worth spending effort/money on the old one or put in a new shed.water between the curveswater between the curvesconcrete covering already inconcrete covering already in

MitchellMc
Bunnings Team Member
Bunnings Team Member

Re: Seal for shed walls

Welcome to the Bunnings Workshop community @Sath. It's great to have you join us, and many thanks for your question about sealing a shed.

 

Believe it or not, in a normal shed installation, that channel is designed to fill up with water and drain away. The outside edge of it is lower than the inside edge, so if it fills up with water, it will flow to the outside. However, your outside section is filled with concrete. Normally it wouldn't fill up as the water would drain out either end. Once again, though, the concrete has likely blocked that escape route.

 

If you remove some concrete from one end and locate that bottom U-shaped trim, you could drill a small hole in it just above ground level to allow the water to drain out. Have a look at the image I've included below. You've solved the issue of the water creeping under the trim, but now it is filling up. Try exposing the trim on the outside and drilling a hole in it.

 

Please let me know if you have any questions.

 

Mitchell



 

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