New Home Begins

[tkappeler]

Drains were approved as expected. The concrete guys are on board with doing the floor first. Early tomorrow is the inspection to see the visqueen is in place and the 6x6 wire mesh is down. They expect to pour on the 26th. Columns will be in place in time to eliminate the need to box around them.

Well, this switch does not change things too much.

 

[sdkubota]

Not sure about your area but where I am from Radon gas is very prevalent. Reason I say this is because a passive system utilizes the rock located below the basement floor and is vented out the top of the house. Probably not an issue in your area but around here it is a major problem.

 

[EddieWalker]

Drains were approved as expected. The concrete guys are on board with doing the floor first. Early tomorrow is the inspection to see the visqueen is in place and the 6x6 wire mesh is down. They expect to pour on the 26th. Columns will be in place in time to eliminate the need to box around them.

Well, this switch does not change things too much.

Are you useing the wire instead of rebar? Do you have it placed on chairs to keep it at the proper height during the pour?

I hate wire mesh with a passion. If done properly, it is better then rebar. What happens is that the guys spreading the concrete walk on the wire and force it to the bottom. They they pretend to pull it up as they go. There are even special tools to do this. Unfortunately, this is all for looks and the wire stays at the bottom of the pad because they just keep walking on it and forcing it down.

When the wire is in the middle of the pad, it is extremely effective. When it is at the bottom of the pad, it is useless.

In some extreme jobs, and those who really want it to be the very best, they will lay wire over rebar and tie them together. Wire is also fine for walkways and small jobs where you don't have to walk on it to spread, scree and float the concrete.

If it was my place and they had just put down wire, I would cancel the job until rebar was used. Nothing is as permanent as concrete. Take the time do do it right.

Eddie

 

[sdkubota]

4" of concrete is not thick enough for rebar to do any good. As far as wire or rebar, both provide additional strength only after a crack has formed. Personally, I would add poly-fiber mesh in the concrete mix. Everyone is entitled to their own beliefs but I would much rather have 4" concrete, un-reinforced, with sawed joints every 8' both directions then adding wire or rebar. All concrete will crack and if you give it a straight line to crack in, little future damage will occur. If you do not provide a weakened path (sawing) you will get random cracking and the possibility for future problems. Attack away (not you Eddie)!

 

[tkappeler]

Eddie, Rebar is not used around here for flat work. I do understand the uselessness of the wire if it is stepped on and left at the bottom of the pour.

Sdkubota, I will have to check, but I believe that the concrete guy is using fibermesh in addition to the wire. I will have to check.

Sorry for the short replies, but it is late and will be able to add more later. Here is a little taste of what I dealt with today. The local weather people did not predict HOW MUCH rain were to get last night. We had 6" of water inside and out.

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Lets see - pump output is 150 gpm. 60 minutes in an hour, 4.5 hours to pump it dry = 40,500 gallons of water remioved

 

[mjncad]

That sucks on the water. I sure hope that foam insulation is closed cell.

As for concrete reinforcing. I just toured a neighbor's house that has major damage in the floor from soil movement. The fiberglass didn't do diddly squat to minimize the damage. Granted, in my neighbor's case, the idiot builder didn't compact and prepare the soil beneath the basement floor properly, which added to the problem. I'd much rather have rebar any day with saw cut control joints.

 

[sdkubota]

Nothing will help concrete placed on a poorly prepared base. Fibermesh works to help stop crack while they are microscopic. In addition and more than anything it provides flexural strendth for concrete increasing its ability to slightly flex. If you have expansive soils, there is nothing that can be done short of installing a structural slab with a void placed below it.

The bright side of all the rain you received is moisture won't be sucked out of the bottom of the slab during placement. You need to also make sure the contractor doesn' add a lot of water while placing. Water = weakened concrete. There are chemicals (Plasticizers) that can be used to lower the slump without compromizing the strength.

 

[EddieWalker]

I'm not a fan of fibers added to concrete. They do add some strength to the mix, but it's minimal and not code anywhere to replace rebar. Depending on what is used, some will stick out of the concrete when it's cured, which can be a pain to deal with. I understand that it's a cheap and easy thing to add to your concrete and it doesn't do any harm, but I would never rely on it to replace rebar.

As for not using rebar on flat work where you live, I would serious look into that and question your source. Since you are getting your home inspected and building to local code, you might be right. Or it might be that they just don't put any emphasis on flat work since it's not structural in your case and anything goes. In most areas of the country, rebar is required, along with size and spacing of it to pass your inspection.

It's your house and you only get one chance to build it as good as you can. Not using rebar and setting it on chairs is one of those things that I've seen done before and will never understand the benifit of saving a few hundred bucks when hundreds of thousands.

Eddie

 

[dstig1]

As for not using rebar on flat work where you live, I would serious look into that and question your source. Since you are getting your home inspected and building to local code, you might be right. Or it might be that they just don't put any emphasis on flat work since it's not structural in your case and anything goes. In most areas of the country, rebar is required, along with size and spacing of it to pass your inspection.

Eddie

I've never heard of rebar being required around here. Wire mesh is the only thing I ever see used in residential. I like rebar too, somewhat for other reasons, but it is rare to see it used in slabs.

 

[sdkubota]

The minimum concerte cover for rebar is 3". That is to protect it from salt, water, etc. Also, the only time rebar does any good for structural strength is when it is placed in the bottom of the concrete slab as steel has great tensile strength where concrete has viturally none. Rebar only begins to take a load wonce the concrete actually cracks. In school we tested concrete beams 6"x6"x24" for flexural strength. Without fiber mesh they would break within a few cycles...with it they could continually take flexural forces indefinately. If you have a good base you will probably not have flexural forces. The number one problem with concrete failing is excessive water added on site...hands down. Concrete strength is solely dependent on the water to cement ratio.