slope on concrete - Contractor Talk - Professional Construction and Remodeling Forum

m1brown · 08-21-2009, 07:49 PM

quick question, if you were pouring a 37' slab to a drain how many inches of slope or drop would you give this slab , it is a mechanics shop. thank you

ScipioAfricanus · 08-21-2009, 07:51 PM

I would find out what the plans say then go from there.

Andy.

cleveman · 08-21-2009, 07:58 PM

3" of slope should do it in a perfect world. But if you have any low spots, they will be a problem. I sloped a 12' slab just 1" once and I had a puddle about 1/8" deep in the middle. I may have "floated" that low spot in, I don't know. Anyway, go 3" as a minimum and more is better.

CrpntrFrk · 08-21-2009, 08:22 PM

1/8" to 1/4" per foot is good rule of thumb

m1brown · 08-21-2009, 08:28 PM

thats exactly what i went 3 inches, the owner wanted 2 inches but we convinced him to go 3 inches , the building is actully 37 * 75 and a drain that is 35 feet long is in the center . The reason he didnt want much slope on it was because of the creapers that the mechanics use on the floor, we told him there will probably be low spots in the floor and he said that is what they make squeegies for , to get rid of the water . Now that concrete is hard and the low spots appear , he got a problem is there a percentage a fellow should use for future sloped floors for garages?

cleveman · 08-21-2009, 08:51 PM

I guess the percentage would be a minimum of 1" for every 12' is 1/120 which is .8333 percent. So just go one percent to be on the safe side, as a MINIMUM.

m1brown · 08-21-2009, 08:55 PM

thanks everybody for the quick answers

BluestoneInc · 09-13-2009, 01:54 PM

3 inches would do it if you can screed the floor flat enough. 1/4" per foot is way to much. There tool boxes will roll to the center of the floor!

scrapecc · 09-13-2009, 03:06 PM

anything over 1 inch in 10 feet will usually develop "bird baths". Thats as far as i will usually push it without telling the customer that they will have puddles.