POURING YOUR BASEMENT CONCRETEFLOOR Basement floors use 20mpa with fibermesh added
-the fiber mesh is an alternative method of basement concretefloor slab reinforcement.. you can go with 10m rebar at 600 centres both ways or no reinforcement at all Concretefloor Slabs are hard work, and should have a crew of at least three. I suggest you use a concrete pump... a line pump is hard work but delivers the concrete at a slower pace which is a benefit... now if you are pumping the pump truck operator can be a huge help or a huge handicap... you want the concrete delivered in manageable quantities... a pump can piss out concrete so fast your head can spin... Be strict and ask for his advice and help... you want a successful concretefloor pour First decide on the elevation of your basement floor... remember if it is a full basement that there are minimum height requirements... but your best elevation is top of slab at 8 feet 3/4" below floor joists.. this just makes framing out the basement so much easier( drywall and stud sizes...when measuring remember your mud sill will sit on top of foundation to carry your joists.. Now snap a chalk line at the proper elevation all around basement wall..this is your top of CONCRETEFLOOR OR top of pour How much fill will you need, minimum depth of concrete is three and a half inches you must have a minimum of six inches of... a good substrate... a load of 4mm and smaller sand is perfect for your needs ... now anything below this can be filled with native backfill if granular or pit run gravel This substrate has to be level it does not hurt to snap a second line on foundation wall 3 1/2inches below top of slab line... get out your rakes and level your substrate to this line... now the substrate has to be compacted hard... do not run a tamper over it once and say done.... do it again and again... now decide were your floor drain is going and slope the sand towards it 1% grade is fine that translates to 1/2 in four feet... if you take a four foot level and stick your finger under the low end and it indicates level you are good to goNow-complete installation of sewer and other subsurface work before pouring re sewer rough or any electrical that needs to be below slab I know this messes up all your hard leveling work but this is the time to do it... it ensures that your sewer lines do not sag... once this is done re smooth your surface do no tamper over sewer lines. Now it should be looking good... layout a vapour barrier 6mil uv protected poly...over lap any seams by 12 inches the weight of the concrete will seal these seams...they do not have to be taped... but the poly should run up the wall and be sealed to the wall with black acoustical seal... this is only needed in areas where radon gas is a problem... You can if you desire use-water repellent rigid insulation around perimeter for insulation purposes the top of the insulation must be even with top of sand substrate Good now... your slab prep is perfect it is a mirror image of your slab to be.. find some nice straight 2x4s and lay them on edge out in parallel lines about 7 feet apart these become your screed sticks when you pour your concrete they give you the elevations of the floor Your crew can pull the concrete with a 2x4 pull stick the third man works behind the screeders he uses a rake and keeps the concrete being pulled to a minimum and also ensures that there is always enough concrete to pull (no voids) I always put a foot wide whythe of concrete down the foundation wall side and float it even with the pour line ... (the pour line can be masked by wet concrete if you do not do this) this foot wide gives the wall side elevation for the screeders to pull level from.. I also put concrete on both sides of the 2x4 screed that lays on edge on ground.. this is just to keep it in position Once you have an eight foot section done... grab your bull float and run it back and forth until surface is relatively smooth.... now continue the next section over do not pull the 2x4 screed out of the concrete until this section is poured and bull floated... now pull the screed out ...this leaves an indent in the fresh concrete that you fill with a few shovel fulls of concrete and then bull float again. Continue until done. Once finished, wait for surface water to disappear and when concrete can hold your weight ... you sink when walking about 1/2inch...jump on with your power trowel with floats on.. power trowel the surface until uniformly smooth.. you will have cream floating in swirls this is good.. hop off and wait for concrete to set some more... and then hop back on... at some point pull the floats off and just use the steel trowels keep doing this until you have a hard dense surface You will need to hand trowel the edges where the power trowel will not reach ... spread your weight on a piece of sheathing or styrofoam insulation to do this Next morning using a circular saw with a concrete blade cut control joints about 3/4" deep -proper
control jointing 4.5 to 6 meters in either direction, and at columns
and changes of widths of slab, -control
joint cuts should be 1/4 the thickness of the slab -cure
for five to seven days ponding, wet sacking etc. if using a curing
membrane ensure that it is compatible with any floor finishes -conretefloor
slabs
on grades should be 200 above finish grades  |
