Waterproofing the base of metal garage/workshop

[RaeT]

HI, We are about to get a metal building installed on a concrete slab and I want to waterproof where they connect as they will only be connected via screws. What do you suggest?

I'm in GA so it gets humid and super hot.

Thanks
Rae

 

[ncornilsen]

is the footprint of the building much smaller than the footprint of the concrete?

 

[RaeT]

The metal building is the shell, I'll be building out the inside to finish it and separate spaces/rooms. The building and slab will be the same size.

 

[loganb]

Grade, grade & more proper grading.

Gutters, downspouts and proper mangt of water away from the building perimeter will go farther than about anything else, and if done improperly will scuttle all other efforts

 

[ncornilsen]

The metal building is the shell, I'll be building out the inside to finish it and separate spaces/rooms. The building and slab will be the same size.

If the building walls are essentially aligned with the edge of the concrete, of within 1-2 inches, you could use a Z shaped flashing that overhangs the edge of the concrete a bit, and tucks under the edge of the metal siding. a sealant under this Z flashing would help prevent wicking. Sealant alone will probably not work long term.

Plus grading, grading grading.

 

[ycgoat]

If the slab is the same size you can either extend the siding down past the edge of the slab, add flashing from under the siding and over the edge of the slab, or caulk the perimeter

 

[KenC]

Don't rely on perimeter caulk only, The base metal should rest on a continuous bead of caulk, between the metal and concrete. This assumes that there is a continuous metal piece on the bottom, like the square tube buildings. Or a purlin at the very bottom. That bead acts as a gasket and doesn't deteriorate since it is not directly exposed to sun and moisture.

 

[billconner]

I'd prefer a PT 2x8 or similar anchored to slab edge and behind metal siding. The siding won't rust because of condensation against slab and the overlapping is natural way to keep water out.

 

[BillK]

Rae,
Have you asked the building installer and the building manufacturer what they normally do ???? I would think that they would be the most knowledgeable ones.

 

[mcbane]

Rae,
Have you asked the building installer and the building manufacturer what they normally do ???? I would think that they would be the most knowledgeable ones.

+1

This is who you should ask. They will have one or more standard details that keep water and rodents out.

 

[ycgoat]

The installers of my square tube building did mot use any water sealing, and it leaks from underneath and through the roll up doors, so ot is on me to resolve after the installation. My plan in order of priority is to
Start with caulk inside and out.
Replace the roll up door seals with larger ones.
Add guttering
Since My slab extends 6” past the building edge, I will either get 6” Z flashing or saw cut the slab and grout the flashing into the slab. This will also require un screwing the bottom of the siding to tuck the flashing behind it.

 

[dcg9381]

+1 on bringing the siding down the edge of the slab and never worry about it. Around here, they do a 1x1" "rat lip" around the perimeter for R-panel. Just bring the R panel 1/16th off that lip and slope the lip to the outside.