Slab Dimension vs. Building Dimension

[bfarroo]

When placing the building on a slab is the slab poured to the dimensions of the building or would it be slightly larger?

 

[Ray-CA]

Our slab is 28x30 but the interior dimensions are 27x29. The stem wall(s) are 6-inches thick and 6-inches high.

Ray

 

[bfarroo]

So if I'm planning on a specific size building the slab should be a foot wider in each dimension or are you talking that once the inside is framed the dimensions are smaller. This will be on a single pour slab with a thickened edge. What I'm looking at is you don't want to have the ribs hanging out off the edge of the concrete or you have to fill them to keep mice or dirt out. so if the outside posts would be set at a multiple of 8' then after the perlin and siding it will be hanging off the end a substantial amount.

 

[dbabicky]

Generally the slab is the same dimension as the outside wall. As long as everything is square, the base plate's outside edge is even, (flush), with the outside edge of the slab.

 

[bfarroo]

ok, then they just fasten the lower rail to the base plate and the siding sits down onto that.

 

[Doug B]

What I'm looking at is you don't want to have the ribs hanging out off the edge of the concrete or you have to fill them to keep mice or dirt out. so if the outside posts would be set at a multiple of 8' then after the perlin and siding it will be hanging off the end a substantial amount.

There should be a foam closure strip to install behind the sidewall metal to mice and debris out.
My personal choice would be to let the purlin and metal extend beyond the slab to help keep moisture off the slab.

 

[timewarp]

You want the siding or trim to hang down outside the slab so that water running down the siding doesn't try to run in on the floor. If the slab is bigger than the building you would want to step the concrete down at the edge of the building so that water wouldn't run in under the wall. Some metal buildings use a piece of sill flashing the corrugated siding sits down on to help keep the critters out.

 

[bfarroo]

Thanks for the info. The are setting the forms today and I atarted thinking about that last night and I wasn't sure. They're setting it to the building dimensions so I should be good

 

[kbs2244]

In my experience outside building dimensions are measured at the sheathing.
So any sideing will over hang a building set on the slab edge.
But that is a good thing.
It keeps the water away.

 

[nehog]

My all metal building came with foundation/slab plans. It was not as simple as just pouring a flat area of concrete, edges and entry points needed special attention, as did the areas where the red iron was bolted down.