Go Back   DIY Chatroom Home Improvement Forum > Home Improvement > Concrete, Stone & Masonry

CLICK HERE AND JOIN OUR COMMUNITY TODAY...IT'S FREE!

Reply
 
Thread Tools Search this Thread Display Modes
Old 01-18-2012, 02:15 AM   #1
Member
 
Join Date: Feb 2010
Location: San Jose, CA
Posts: 45
Rewards Points: 25
Default

Question about slope of garage slab foundation


I am going to pour my first slab foundation soon for a garage. It requires 1" per 10' slope to door. My question is: A)should I make the whole slab sloped, or B) make the edge of the slab level.

If I make the whole slab sloped, I need to cut studs to make top plates level. So that roof trusses will be level too.
If I make the edge of the slab level, it will save me some stud cut. However I don't know if that's the right way.

My dear friends, could you give me a clue?

pttcc is offline   Reply With Quote
Old 01-18-2012, 02:28 AM   #2
Residential Designer
 
AndyGump's Avatar
 
Join Date: Sep 2010
Location: Orange County CA.
Posts: 1,316
Rewards Points: 548
Send a message via Skype™ to AndyGump
Default

Question about slope of garage slab foundation


I am sure that your plans show that you have a min. 8" high x 6" wide conc. stem wall around the perimeter of the garage.

It should show that the stem wall is level all round.

Andy.

AndyGump is offline   Reply With Quote
The Following User Says Thank You to AndyGump For This Useful Post:
pttcc (01-18-2012)
Old 01-18-2012, 02:50 AM   #3
Member
 
Join Date: Feb 2010
Location: San Jose, CA
Posts: 45
Rewards Points: 25
Default

Question about slope of garage slab foundation


The plan doesn't show that. It's monolithic slab of single pour with turned down edges.
pttcc is offline   Reply With Quote
Old 01-18-2012, 02:58 AM   #4
Residential Designer
 
AndyGump's Avatar
 
Join Date: Sep 2010
Location: Orange County CA.
Posts: 1,316
Rewards Points: 548
Send a message via Skype™ to AndyGump
Default

Question about slope of garage slab foundation


But you are in California, a stem wall in a garage is prescriptive.

How did the engineer or Archy get by that one?

Could you post the plan or the detail showing the garage area?

Andy.
AndyGump is offline   Reply With Quote
The Following User Says Thank You to AndyGump For This Useful Post:
pttcc (01-18-2012)
Old 01-18-2012, 03:02 AM   #5
Member
 
Join Date: Feb 2010
Location: San Jose, CA
Posts: 45
Rewards Points: 25
Default

Question about slope of garage slab foundation


Thanks Andy for the heads up. I will get it fixed!
pttcc is offline   Reply With Quote
Old 01-18-2012, 03:06 AM   #6
Residential Designer
 
AndyGump's Avatar
 
Join Date: Sep 2010
Location: Orange County CA.
Posts: 1,316
Rewards Points: 548
Send a message via Skype™ to AndyGump
Default

Question about slope of garage slab foundation


BTW, on the slope issue:

R309.1 Floor surface. Garage floor surfaces shall be of approved noncombustible material.

The area of floor used for parking of automobiles or other vehicles shall be sloped to facilitate the movement of liquids to a drain or toward the main vehicle entry doorway.

Andy.
AndyGump is offline   Reply With Quote
The Following 2 Users Say Thank You to AndyGump For This Useful Post:
mae-ling (01-18-2012), pttcc (01-18-2012)
Old 01-18-2012, 07:11 AM   #7
Concrete & Masonry
 
Join Date: Nov 2008
Location: Wisconsin
Posts: 2,792
Rewards Points: 2,136
Default

Question about slope of garage slab foundation


As Andy noted, a curb or stem wall formed and poured the same time as the slab is the correct way, code required or not.

As for pitch, 1" per 10 feet is extremely minimal, and a guarantee to hold water w/o an absolutely perfect installation. If you're DIY'ing this slab, you're going to have a hard time with the perfection part. Better to shoot for about 1" per 5'.
jomama45 is online now   Reply With Quote
The Following User Says Thank You to jomama45 For This Useful Post:
pttcc (01-18-2012)
Old 01-18-2012, 10:20 AM   #8
Old School
 
Willie T's Avatar
 
Join Date: Jan 2009
Location: St. Petersburg, FL Minds of moderate caliber ordinarily condemn everything which is beyond them.
Posts: 3,634
Rewards Points: 2,000
Default

Question about slope of garage slab foundation


And also be careful that you don't inadvertantly create a puddle trap of a low area all across the bottom of the pull-down door.
__________________
"True eloquence consists in saying all that is necessary, and only that which is."
François Duc de La Rochefoucauld
Willie T
Willie T is offline   Reply With Quote
The Following User Says Thank You to Willie T For This Useful Post:
pttcc (01-18-2012)
Old 01-18-2012, 03:22 PM   #9
Member
 
Join Date: Feb 2010
Location: San Jose, CA
Posts: 45
Rewards Points: 25
Default

Question about slope of garage slab foundation


I visited San Jose city hall this morning and talked to inspectors. According to them, monolithic slab is ok for garage foundation.
pttcc is offline   Reply With Quote
Old 01-18-2012, 03:39 PM   #10
Residential Designer
 
AndyGump's Avatar
 
Join Date: Sep 2010
Location: Orange County CA.
Posts: 1,316
Rewards Points: 548
Send a message via Skype™ to AndyGump
Default

Question about slope of garage slab foundation


HI Pete, (I'll just call you Pete if you don't mind) a monolithic slab is fine yes.

But usually you will have a detail something like this to show the garage wall attachment to the foundation showing a stem wall.

Your plans do not have this?

This is just something I threw together to illustrate, your plans would be much more detailed than this.

Andy.
Attached Thumbnails
Question about slope of garage slab foundation-garage-detail.jpg  
AndyGump is offline   Reply With Quote
The Following 3 Users Say Thank You to AndyGump For This Useful Post:
jomama45 (01-18-2012), pttcc (01-18-2012), Willie T (01-18-2012)
Old 01-18-2012, 04:28 PM   #11
Member
 
firehawkmph's Avatar
 
Join Date: Dec 2009
Location: Near Cleveland, Ohio
Posts: 1,585
Rewards Points: 1,002
Default

Question about slope of garage slab foundation


Quote:
Originally Posted by jomama45 View Post
As for pitch, 1" per 10 feet is extremely minimal, and a guarantee to hold water w/o an absolutely perfect installation. If you're DIY'ing this slab, you're going to have a hard time with the perfection part. Better to shoot for about 1" per 5'.
Jomama,
So if he has a garage say 24' deep, your talking almost 5" of fall. That's seems like way too much. Maybe it's different in CA, but here in Ohio, 1 1/2" of pitch towards the door would be plenty. If you end up with puddles, then the guys didn't do a good job setting their grade pins.
Mike Hawkins
firehawkmph is offline   Reply With Quote
The Following User Says Thank You to firehawkmph For This Useful Post:
pttcc (01-18-2012)
Old 01-18-2012, 04:40 PM   #12
Member
 
concretemasonry's Avatar
 
Join Date: Oct 2006
Location: Minneapolis/St. Paul, Minnesota - Latitude 45.057 Longitude -93.074
Posts: 3,819
Rewards Points: 2,126
Default

Question about slope of garage slab foundation


firehawk -

The slope and construction is a local need and preference and most codes allow for variations.

In many places, a true "floating slab" inside (and not connected to) the stem wall (concrete or block) is preferred. The floor slopes from a level at the the stem wall down to the desired location. Usually the stem wall is used as a raised curb. The slab can slope to the overhead door or to a central floor drain. A standard for decades.

If you have to deal with frost footings at the frost level it is much more practical and gives a garage that can be easily drained and kept clean, especially if it is an attached garage.

Dick
concretemasonry is online now   Reply With Quote
The Following User Says Thank You to concretemasonry For This Useful Post:
pttcc (01-18-2012)
Old 01-18-2012, 05:09 PM   #13
Concrete & Masonry
 
Join Date: Nov 2008
Location: Wisconsin
Posts: 2,792
Rewards Points: 2,136
Default

Question about slope of garage slab foundation


Quote:
Originally Posted by firehawkmph View Post
Jomama,
So if he has a garage say 24' deep, your talking almost 5" of fall. That's seems like way too much. Maybe it's different in CA, but here in Ohio, 1 1/2" of pitch towards the door would be plenty. If you end up with puddles, then the guys didn't do a good job setting their grade pins.
Mike Hawkins
We almost always go with 3.5" (mostly because the height of a 2x4 is the simplest way to do it) on a standard depth garage. On a 24' depth, it's not uncommon to leave the back few feet level for ease in installing cabinets/workbench/shelves/etc... The pitch generally just needs to extend a little past the length of the vehicles parked in it. Here, the main concern is that ice/snow/rain that drip off of the vehicle finds it's way to the OH.

Have I gone flatter than 1" per 5'?? Certainly, but i do it for a living and I know our limits from pouring thousands of yards of concrete. More importantly, 95% of the time I'm the guy who goes back to saw joints, and I witness the flatness firsthand when snapping lines. From my experience, I wouldn't recommend that a DIY'er try to install a floor with as little as 1" in 10' unless they are willing to accept some puddles and standing water.
jomama45 is online now   Reply With Quote
The Following 2 Users Say Thank You to jomama45 For This Useful Post:
Gary in WA (01-18-2012), pttcc (01-18-2012)
Old 01-18-2012, 09:56 PM   #14
JOATMON
 
ddawg16's Avatar
 
Join Date: Aug 2011
Location: S. California
Posts: 7,581
Rewards Points: 2,492
Default

Question about slope of garage slab foundation


Quote:
Originally Posted by firehawkmph View Post
Jomama,
So if he has a garage say 24' deep, your talking almost 5" of fall. That's seems like way too much. Maybe it's different in CA, but here in Ohio, 1 1/2" of pitch towards the door would be plenty. If you end up with puddles, then the guys didn't do a good job setting their grade pins.
Mike Hawkins
Recheck your math....his spec was 1" per 10'....on a 24' garage, that would be about 2.5"....which is a lot. My garge is 25" and it slopes about 1"....and I don't have an issue getting water out.

pttc.....I would 'highly' suggest stem walls. Without them, your going to be cutting every single 2x4 stud a different length if you want you roof to be flat.

Click on the link in my signature for the Garage build....I went through it about 2 years ago.
__________________
Even if you are on the right track, you will still get run over if you just sit there.

My 2-Story Addition Build in Progress Link ... My Garage Build Link and My Jeep Build Link
ddawg16 is online now   Reply With Quote
The Following User Says Thank You to ddawg16 For This Useful Post:
pttcc (01-18-2012)
Old 01-18-2012, 10:07 PM   #15
Member
 
Join Date: Nov 2011
Location: Hartfield VA
Posts: 27,518
Rewards Points: 4,152
Default

Question about slope of garage slab foundation


Personaly I'd never suggest a DIY try and pore there own slab, way to many ways for it to go wrong. As you guys know it's a one shot deal.
Without a stem wall behond what's been mentioned is the siding would be low and rot from splash back.
We also all know if the foundations messed up everything else above it's going to be messed up.

joecaption is offline   Reply With Quote
The Following 2 Users Say Thank You to joecaption For This Useful Post:
concretemasonry (01-18-2012), pttcc (01-18-2012)
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Expanding Garage INTO house (goodbye Den) texaopian Building & Construction 16 11-07-2011 11:32 PM
Garage insulation question silverfox103 Insulation 0 10-05-2011 10:10 AM
Garage remodel - adequate foundation? WillK Building & Construction 1 01-21-2011 02:50 PM
Replacement concrete garage floor, dowelled into foundation? Niffumdutz Building & Construction 5 02-19-2010 09:31 PM
Garage Foundation cibula11 Building & Construction 5 08-08-2009 02:36 PM




Top of Page | View New Posts

Copyright © 2003-2014 Escalate Media. All Rights Reserved.