I'm in the process of submitting bids for replacing the concrete floor in my basement and wanted to get some advice on what to put in the contract/bid specification:
I'm replacing it for two reasons: 1. To gain additional height (to get to habitable height); and 2. To reduce the amount of moisture wicking up through the slab.
The basement is about 600 square feet. There are two slabs--one poured right on top of the other. The contractor will be excavating a ramp down into the basement, remove a section of the concrete block, then pull the concrete out after jack hammering it up (no other access other than internal stairs). I'm having them redo all the plumbing under the basement floor, adding in stubs for the planned plumbing, and redoing the water and sewer lines from the house to the street. They will be putting in an interior drain system and a sump pit.
I have a few questions on what to specify in my bid request:
1. Based on my reading, I will specify the following cement: 'Pour new 4” thick floor with concrete that has the following minimum specifications: 3,000 PSI @ or before 28 days, 4 1/2 sack mix minimum.'
2. For a residential slab, do I need reinforcement, either welded wire frame or rebar? I put the following text in:
'Install welded wire fabric with a minimum of WWF 6” x6” -10 /10 (AKA 6 x 6 - W1.4 x W1.4). Install ONE support chairs/dobies per FOUR square feet so that the wire will not be displaced during concrete pour. Use plywood walkboards during pour to avoid crushing chairs’
3. Can I use a plastic fiber admixture instead of the WWF?
4. Do I need control joints? The basement is a 25' x 25' square with the load carrying beam in the center. One one side, is a 7'x12' bump out. I was going to specify a control joint under the beam where the two support columns were, and a control joint where the bump out and square meet. Is that sufficent?
5. Should I request PVC or ABS under the slab?
6. One contractor put the following in his bid, 'Install EPS Board around perimeter for cricket'. What is a cricket?
7 One contractor wants 50% to start, and 50% to finish; the other wants 1/3 upon starting, 1/3 upon prep (what does that mean), and 1/3 at completion. The total job is in the $20,000 range, and I'm not comfortable giving anybody $10,000 for their promiste to do the job.
Is the following payment schedule reasonable, and which will allow the contractor to pay his employees/subs?
Sign contract - 10%
Ramp excavation complete and block removed - 10%
Concrete Floor Removed - 25%
Plumbing roughed in and inspected - 10%
After concrete pour - 25%
Final payment after final inspections - 20%