As a Tulsa commercial contractor, I spoke last week about the differences in a commercial building versus a residential building. I talked about how the dirt work and Geotech report go together to create a stable pad along with the structural and civil engineers so that a slab in building Would be able to be put on it safely. This week one of the ways a commercial building differs from my residential building is in the concrete and the reinforcement of the concrete and the slab itself.
No in a commercial building A Tulsa commercial contractor is required to put 2-inch rigid insulation in the footings surrounding the pad below grade. They are because I am a Tulsa commercial contractor I don’t know if a residential contractor is required to put 2-inch rigid insulation in the footings. Last week I also spoke about out of the structural engineer has to take into account the way of the building and how the soil need to be prepared to withstand that way and the same goes with the concrete.
The structural engineer will have to tell the architect and ultimately the Tulsa commercial contractor what needs to be below ground so that the building slab can rest on the footings. Now once the structural engineer knows what type of building it’s going to be and for instants if it’s going to be a pre-engineered metal building then the weight is not going to be spread uniformly across the slab or along the edge of the building the weight will be concentrated at the point at where the column rest and beneath the column will be what’s called a column pad.
Now the structural engineer will design this column pad to withstand the weight of this section of building and disperse that into the soil because typically the column tapers down to a base plate. So the column on one in may be 2 feet wide by 10 inches long and you know a half inch thick and that tapers down to an 8 x 10 inch base plate and so in less than a square foot you have a huge amount of weight resting so that way it needs to be carried down pass the slab and into the footing and then spread out from a square foot to a greater distance.
Depending on the recommendation from the structural engineer the call pad will have various degrees of rebar. Rebar is a piece of steel with the ridges in it and it gives the concrete something to mold too and gives it strength and without rebar concrete would essentially just crumble. Depending on the way of the building the structural engineer and architect will develop a footing schedule this schedule will lay out the size of the rebar which way it’s supposed to go the amount of stirrups the cage being built the distance from the edge of the concrete to rebar and all of these things matter in giving the footing the required amount of Strength.
What Else Can You Find From Tulsa commercial contractor?
So in a situation where you have a continuous footing into a column pad you may have something like number three rebar continuous were 18 inch number four dowels on top and bottom with the minimum inch coverage with number five stirrups end it is up to the contractor to do is to dig a hole put the rebar In its place tie it together and because it is so important usually the architect and city officials will want to be on site To review and approve before the concrete is poured over the rebar.
What’s the footing has been poured and give them time to harden the preparation for the slab will begin one the differences for a Tulsa commercial contractor versus a residential contractor is the amount of testing. I am not too familiar with the testing requirements for residential concrete but the Tulsa commercial contractor has To have independent testing done in the testing company will report those results at 7, 28, 56 and 120 days as well as what they call a slump test where the concrete can’t be too wet when it comes out of the truck.
The samples from the pool will be taken to the testing lab and there is it a different PSI rating on the different country no 3500 psi shit at seven days should only cried a certain well and if it cracks more than that or it doesn’t break properly then the Tulsa commercial contractor could have to fix it or remedy it in some way. But if the seven-day test looks good the Tulsa commercial contractor could start looking at pouring the slab for the building. In a typical slab for a commercial building A Tulsa commercial contractor would be given plans that day we want 4-inch base with a 6-inch slab and at the end of the slab a thickened edge of 8 inches at the footing.
So with that means is on top of the pad they’ll be gravel brought in and put out to a certain point you didn’t put vapor barrier over the gravel and then you would lay out your rebar for the structural engineers request and for a 6 inch slab you would want your rebar that is running each way to be approximately 3 inches off the egg base so that the rebar is as close to center of that slab as you can get. Now part of the thickened edge would be over the footing so that the slab has more concrete to rest on top of the footer and this will keep the edge from cracking.
In a residential setting the framing is typically disbursed equally over the slab like the rigid frame of a pre-engineered metal building may sit at points every 25 feet but a wood frame wall is going to disperse the way all along the wall and not just add those certain points so you don’t have to have the large column pad and footing you would just have a small continuous footing around the perimeter of the slab and then a second edge again for the slab to rest on And not crack under the weight of the building. Next time I will talk about the slab itself as far as control joints isolation joints and move on to other ways in which being a Tulsa commercial contractor is different from being a residential contractor in the Tulsa area.