Seal the base of a steel shed to concrete

Frank Jnr

I'm after putting up a Yardmaster steel shed on a rough concrete driveway extension that is slightly sloped away from the house to allow for drainage.

The downside of this is that rainwater is flowing through the shed on it's way to the drain. The gaps between the shed base & the concrete vary slightly, due to the rough finish of the concrete, but the biggest gap is about 1cm. Is there anyway that I can seal the metal base of the shed to the concrete so that the rainwater runs around the shed and not through it?

I'm assuming some form of silicone or gutter / marine sealant will do the trick for sealing the gaps but do I need to seal the concrete first with the likes of "Thompsons Concrete Seal" in order for the sealant to properly adhere to the concrete as well as the metal?


Thanks in advance,

Frank.

reilig

Frank Jnr wrote: »

I'm after putting up a Yardmaster steel shed on a rough concrete driveway extension that is slightly sloped away from the house to allow for drainage.

The downside of this is that rainwater is flowing through the shed on it's way to the drain. The gaps between the shed base & the concrete vary slightly, due to the rough finish of the concrete, but the biggest gap is about 1cm. Is there anyway that I can seal the metal base of the shed to the concrete so that the rainwater runs around the shed and not through it?

I'm assuming some form of silicone or gutter / marine sealant will do the trick for sealing the gaps but do I need to seal the concrete first with the likes of "Thompsons Concrete Seal" in order for the sealant to properly adhere to the concrete as well as the metal?


Thanks in advance,

Frank.

A bag of cement and a barrow of sand. Mix up a bit and make a little ramp around the shed base that will prevent the water flowing through the shed and force it to flow around it. Use a drill to drill some holes in the concrete before you put in the ramp, get some steel bars and set them upright. They will give the concrete that you pour some strength and prevent it from breaking a few years down the line.

Frank Jnr

Thanks for the reply reilig but I'm a bit reluctant to use concrete as from my very limited experience with concrete or cement I know it will eventually crack, break up and start leaking, I figured that sealing the shed base directly to the concrete with a flexible sealant would be a more durable solution.

Besides, if I build a small concrete ramp around the base of the shed will that not just act as a rain water trap?

Buford T Justice

Frank Jnr wrote: »

Besides, if I build a small concrete ramp around the base of the shed will that not just act as a rain water trap?

Yes it will. If rainwater is naturally going to flow towards the shed, then putting down a sand and cement base is going to be pointless, the water will get in between the joint of this and the concrete and lift it.

Best bet is do dig a drain channel across the front of the shed and install a drain into it to divert the water around the shed and away somewhere else.
Like below, but you can also get them in plastic

antiskeptic

Frank Jnr wrote: »

Thanks for the reply reilig but I'm a bit reluctant to use concrete as from my very limited experience with concrete or cement I know it will eventually crack, break up and start leaking, I figured that sealing the shed base directly to the concrete with a flexible sealant would be a more durable solution.

Besides, if I build a small concrete ramp around the base of the shed will that not just act as a rain water trap?

I'd go the tec7 route myself: relatively cheap and fast. I'd take a little extra care to work it with the nozzle tip into undulations in the concrete surface in order to ensure seamless adhesion. Aside from that it's straightforward gap filling from a tube.

MidlandsM

Whats Tec7 please? interested.

Jokesetal

The channel seems to be the best idea, if you want it done right. I've tried the sealing route on different things over the years and it works well initially but then you'll run into faster rust rates and resealing problems when you get a warm summer and the seal rises (shrinks). You'd need to get a soak hole though.... if you're not near a sewage mains.

Otherwise you could run a grinder along in front of the shed and put down a plastic strip. Then you can seal that (a bit like lead flashing I suppose, but without the staining).

masonry solutions

All good hardwares have tec7 it come in a silicone tube. Its not an ideal solution but ok for in the short term. Ideally you need pour a small concrete base and raise the shed up which will also stop rising damp. i could give you a price for this if intrested.

masonry solutions

No you dont need to prime the concrete to use tec7 just make sure its dust free

Frank Jnr

Evening all,

Thanks for the replies.

I think I'll go with the Tec7 sealing, I don't want to do any more cutting, building or digging. While researching another issue with metal sheds, condensation, I discovered it's a good idea to seal the concrete with vapour seal paint.

So what I'll probably do is paint the concrete floor in the shed with vapour seal paint then seal the shed base to the new paint job.

I know it's not ideal but it'll do for now!


Regards,

Frank.

Carlow52

I would go with Foilband from here:
http://www.hodgsonsealants.com/productpage/Laminated-Butyl-Sealants/

Put a 2" strip on the concrete all the way around the shed and then flash bottom of shed to it.
Lifetime job.