New garage build sequence question

[WAKman]

My original plan with my new 960 sq ft garage was to have the slab poured before the building was framed. However, we are now into December here in sunny Seattle, which means rain. My builder has suggested that we finish the foundation (footers are in, foundation walls about to be poured) and then begin framing, thus enclosing everything before the slab is poured. This will allow the slab to be poured and finished without worry of rain.

Here is where we stand as of this morning, with the forms in place for the wall pour.

Anyone have thoughts on doing things in the sequence described above?

 

[matt_i]

Once the shown forms are stripped is there back fill & prep to be done or is it basically time to pour?

Biggest question would be if the concrete truck can access far enough inside the building to fill up the floor without use of special pumps (etc). Otherwise said I don't think the concrete truck is going to be able to drive in under the 8' garage door header. The chute will of course be inside the building, but will it be far enough out not to completely wear out the crew? I feel like the potential to get a better job is considerably higher if the crew isn't worn slap out by the time it comes to screeding, power troweling, and hand-trowel finishing.

If the builder is managing the entire process as a general contractor, then I don't see the downside to following their recommendations. They could be trying to alleviate a bottleneck whereby the concrete guys are working wide open and the framers are looking for work.

 

[ArcticGabe]

It might actually be advantageous to do it in that order. If you build a roof first then pour concrete under it, the concrete will not be exposed to sun so it will cure slower which will make for a better slab. I wouldn't worry too much about concrete truck access. When they build mine, the truck stayed on the street and they used a buggy to bring concrete to the construction site. They do this to keep the concrete truck from destroying the existing driveway.

 

[HoosierBuddy]

No real experience other than with my 2006 build where we did the footer, then framing and roof, then floor last. It worked out well.

Phil

 

[nadogail]

If you are in doubt, ask an experienced person for their opinion.

Seattle is Seattle, what works in Tucson might not work in Seattle.

Go with local knowledge.

 

[Kevin54]

Most floors get poured after the foundation is up.

 

[WAKman]

Thanks all--good advice. The reason the builder wants to do it in this order is because we are worried about rain pock-marking the concrete. We poured the footers during a rain storm, and I was surprised how much the droplets messed up the top. Didn't matter on the footers, but will on the floor slab.

Makes sens eot me, I just wondered if there was something I didn't know about.

 

[Jayman17]

"If you build a roof first then pour concrete under it, the concrete will not be exposed to sun..."

No worries there, the sun won't be appearing again in Seattle until July 5 2020

Jay

 

[WAKman]

If you build a roof first then pour concrete under it, the concrete will not be exposed to sun...

No worries there, the sun won't be appearing again in Seattle until July 5 2020

Jay

If then!

 

[wssix99]

Not a problem. As mentioned above, just plan access for machines, chutes, etc. (ie: You may need to leave some holes in walls temporarily to give you the access you need to chute concrete inside the house.) Having a garage you can drive a concrete mixer through also helps a ton!

 

[zoepop]

I'm in the same boat although due to temps not rain. My concrete guy wants the building up so we can heat it. Not a bad thing to wait. The longer the fill has to settle the better for the slab

 

[larry4406]

On my last shop I had the slab poured after the framing and roof were on just as you suggested. As long as none of your framing is off the slab, then you are good to go. Access for later pouring slab is key.

 

[vavet]

We had our house built 4 years ago and my detached garage built 2 years ago. The attached garage floor was poured after the framing was done. In fact, I was a little miffed when they did it because we wanted to write our initial in the wet concrete, but we were never told. No matter, we were able to do it when they poured the apron for the driveway.

For the detached garage, the floor was poured after the stem walls were up, but before the framing. The downside to that was that the carpenter then shot nails through the concrete floor for diagonal bracing for the walls. I didn't even know you COULD do that, but apparently so. I'm a bit miffed everytime I see those holes in my floor now, but what's done is done.

 

[CraigStu]

Mine addon bay was a lot smaller at 16x22 but they did the floor pour almost last. Contractor said a couple of advantages. The fill had a longer time to settle. The date of that final pour could be juggled a lot easier compared to the other steps in the build. We were working through the winter so it would be easy to heat the nearly completed garage so the concrete could set up properly. He felt the only downside was that it is nicer for the guys to work on concrete than gravel but the other advantages out weighed that thought.

 

[ard]

Should not be a problem

Actually, if you care about the visual finish of the slab (like you will be staining or uding a clear sealer) you may hold off until (almost) all construction is done. Or at least heavy framing.

 

[WAKman]

Should not be a problem

Actually, if you care about the visual finish of the slab (like you will be staining or uding a clear sealer) you may hold off until (almost) all construction is done. Or at least heavy framing.

That's a good point, sir. It will also allow me to place the electrical runs in the slab.

 

[PNWguy]

When I asked my contractor about framing first and pouring the slab later, he was concerned about the concrete finishers not having room to work.

I'm much drier than Seattle, but it's rainy season for a bit here as well.

 

[ItsNemo]

Mine addon bay was a lot smaller at 16x22 but they did the floor pour almost last. Contractor said a couple of advantages. The fill had a longer time to settle. The date of that final pour could be juggled a lot easier compared to the other steps in the build. We were working through the winter so it would be easy to heat the nearly completed garage so the concrete could set up properly. He felt the only downside was that it is nicer for the guys to work on concrete than gravel but the other advantages out weighed that thought.

This might be a fair point...if they're framing walls on the ground, it would sure be nice if that ground is flat/level to make for straighter walls.

 

[rburke65]

On my build everything was finished on the outside, doors, windows in, then placed t(e concrete floor

 

[btdobie]

Most of the builders I have dealt with pour the slab after framing and sheeting the exterior. The slabs always look great.

 

[wssix99]

When I asked my contractor about framing first and pouring the slab later, he was concerned about the concrete finishers not having room to work.

Definitely need to make the garage bigger, then.

 

[PNWguy]

Definitely need to make the garage bigger, then.

The slab is 40 x 84.
He pitched it to me like "the guys will have issues with the long handled trowels, screeds, etc.

Sounds like I may have an issue. I'd like to get the damn thing framed ASAP. We are entering a few months of either warm & rainy or cold and dry. I'd much rather pour on a warm, wet day - if the slab is covered.

 

[wssix99]

That's a huge space. Odd that the contractor can't figure out how to pour and trowel inside like everyone else does.

 

[xdrag48]

I did the concrete before I framed my walls,as the rear of mine was four feet up from the ground.We had rain coming and as soon as the floor was done we set the trusses on the foundation walls and put a blue tarp over them and let it set until the rain had stopped.It sat for 3 days and all was well,nice and dry.
It was also nice to be able to build the walls on the floor too.

 

[aventino68]

That's a huge space. Odd that the contractor can't figure out how to pour and trowel inside like everyone else does.

Thats what I was thinking at 40' deep, its not like they can finish it all from the sides

 

[JamesW84]

I had my walls and floor poured and then framed. My pneumatic tired scissor lift doesn't get around on gravel/dirt as well unless it's pretty flat, so I'm glad I did it that way.

I will say that I've had hydraulic fluid leaks, dropped hammers, nailed through a board or two and thus marred my floor. I've tried very hard to not damage my floor. Dawn took the hydraulic fluid up. It was nice to be able to frame the walls on the floor.

 

[Wes Tex]

With my 30x40 all metal shop, the outside support poles were set first then the floor was poured. The concrete trucks drove down the alley next to the site to unload. A finished floor made it easy to maneuver equipment to complete the shop. In this area of Texas I see most slabs poured first then the surrounding structure completed. I assume this is somewhat influenced by the weather. Rain? What rain?

 

[wssix99]

In this area of Texas I see most slabs poured first then the surrounding structure completed. I assume this is somewhat influenced by the weather. Rain? What rain?

In some parts of TX, (in areas where the ground doesn't freeze/heave) you can integrate the wall foundation with the slab. (I expect that you see a lot of that.) So in those cases, you need to pour the whole slab first. In order to pour the slab after, one needs deep foundations and a separate floating slab.