My garage is 28 x 28 and I’ll be using a rebar grid for strength and possibly fiber concrete.
How thick should I go…..4 inches or 6 inches?
I also have a floor drain on both sides,do I just screte off of the drain in a circle to the outside level line to get my taper right?
Thanks
Rupert
Replies
Attached drawing legend:- Aqua = scree boards
- Red = dowels
- Green = dowels
- Orange = Direction concrete is poured in the sections
- Section #'s are outside the main drawing
- The top of the drawing is the back of the garage.
- The rebar shown in sec 2 of the drawing is to give rebar detail at drains.
Make sure scree boards are cut and laid so vert #2 will slide past horiz #4. Horiz's #3 slides past vert #4. Vert #4 past horiz #4.
The verticle scree boards are level. the horizontal ones are tapered to meet the drains.
The red dowels #4x2' are put in before any pour. Drill the dowel holes in the scree's with clearance. All dowels except green #3 and the horiz dowel above the horiz scree in the drawing should be above the rebar. Green 3 and it's mate below rebar.
Rebar in sec 1 is in place, in sec 2, it is pulled away from sec 1. rebar in sec 3 is pulled away from sec 1, and in sec 4, it is pulled away from sec's 3 and 2. (2-3" clear of the dowels)
Mark on the outside form boards the left edge of the vert screes and the top edge of the horiz screes, to pull a line for exapnsion joints. Expansion joint should align with cold joints.
Pour sec 1, make sure dowels coming out of mud are parallel. scree sec 1, recheck dowels for parallel. Remove scree #2. set 1x4 on sec 1 next to scree #2 position.
Insert 1/2" wood dowel into green dowel #2 location 12" into sec 2. Pour sec 2, scree off sec 2 to 1x4 with 3/4" notched scree. while screeing sec 2, fresno sec 1.
Remove scree #3, insert green dowel #3, set sec 3 rebar, pour sec 3, scree sec 3, fresno sec 2. Fresno over cold joint.
remove 2 #4 scree's, replace wood dowel with rebar dowel, finish pour. Do expansion joints.
Keep the slab damp for 14 days with no heavy loads to help prevent cracking.
How thick should I go.....4 inches or 6 inches?
5 1/2". You want a minimum of 4" at the drains and for good drainage a slope of 1/8" / foot. If you don't mind helping the water get to the drains, you might try 1/16" / foot. For ease of construction I would use 2x6 for external forms and work from there. That gives 12 eighths per 14'
SamT
Edited 9/22/2003 3:56:45 PM ET by SamT
Edited 9/22/2003 4:13:22 PM ET by SamT
DIY or pay-to-do?
Agree with the 5-1/2" for pay-to-do as many (maybe not yours) 'professionals' will likely pour soup. For DIY you can go with 3-1/2" (2x4) if you keep a stiff mix with 6 sack or better cement content. Mine are 3-1/2 and no cracks in 20 years, often load with 20K# trailer with tires at 100+ psi, reinforcement is simply old fencing.
I agree with the 4" to 5-1/2" Min. on slab thickness.
BUT!!
The most important consideration here is substrate preparation!!!
Good drainage and The proper amount of compacted Gravel will Be your best defense against cracks, heavin and buckling.
Also Isolate any pads for posts from the slab.
Are you pouring ovcer a foundation or will this be a thickened edge slab?
What is your climate/frostline?
Mr T
Do not try this at home!
I am an Experienced Professional!
Don't make the mistake of tying the slab to the footings walls. Install those jute mat strips or the foam strips used for pool decks around the perimeter and one down the center for expansion joints. All the garage slabs with big cracks down the center has its slab tied to the footings.
Also, pour the slab after the garage roof sheathing/framing is up. Direct sunlight can cause cracks, I've seen cracks where the shade line is.
My location is central PA. I have the height to go 5 1/2 and I am planning on pouring after the walls and roof are on and with all the time restaints I will most likely pour in the spring unless things go well. It's been settling for a year now as I've been working on the house. But I still have to tie in the drains to the outside which I will tamp afterwards. I will have expansion joints around the perimeter and down the center.
Thanks
Rupert
You're allowed floor drains in a garage? Up here, if you put in a floor drain, it has to go to an oil/water separator. So most people just put a slope on the floor toward the door.
Cario
I'm out in the country with no ordinances, I operate water and wastewater plants so I know what you mean as far as oil and grease goes.
My drains will just be for snow melt and winter truck washing
Rupert