Concrete floor issues

[picturemark]

My house has a second story terrace that's over my laundry room. The construction is a flat concrete roof that originally had a brick surface on top of it that became the floor of the terrace. It's about 12X20 feet. Around 8 years ago I had the brick jackhammered off because of serious spalling. The contractor then put down a rubber membrane that folds up the parapet wall about 4 inches. A pump truck then reached over the top of the house and poured a new concrete floor. Expansion joints were formed and two coats of SikaTop 144 was applied to waterproof.
Unfortunately, I don't think the concrete was formed to have water drain properly and subsequent freeze thaw cycles have caused spalling in one corner about 4X4 feet.
I chipped out the loose concrete (about 1/4 to 1 inch deep). I'm planning on putting QuickCrete down.
My problem is that I've got the rest of the terrace covered in slightly degraded Siketop coating. 5 Gallons of that stuff is going to cost a little over $200.00. They say you need two coats about 2 hours apart rolling it on. But is start drying in the bucket before that.
I'm concerned that I'm only doing a cosmetic repair (I'm not addressing the slope of the floor). I'm worried that if I try another waterproofing product (it has to stand up to light foot traffic and full sun) I"ll have bonding problems with the old coating.
Anybody have a strategy they're willing to share?
Thanks,
Mark

 

[glennjanie]

Hey Mark:
Your problem is quite a challenge. I would consider another membrane roof over the whole floor; but, this time, I would use the fiberglass base that makes the roof pitch more pronounced. Fiberglass is available in various tapered thicknesses to make a continous pitch for drainage. The only problem is, I don't know how well it will stand up to foot traffic and especially to chair and table legs. I know that some roofs have several thick pads for walking paths, like stepping stones. If the chair and table legs were placed on something to disperse the weight there may be no problem at all.
Sorry I can't be more definite about this; perhaps you can google the product and find out how much traffic it can stand.
Glenn

 

[Square Eye]

The aggregate in quickcrete is going to be too much for a 1/4 inch thick patch. Floor leveler will hold better and will be adequate in the shallow areas. There is also a product that prepares the surface before you make the repair.
You pour it on and spread it out, it helps bond the patching material to the old surface.
Do the deeper area first and then do the shallow area and the feathering with the floor leveler after the concrete sets.