Anybody ever seen this? Sides of garage heave slot at edges?

jsimon77 · Jun 14, 2019

All the garages that I have had in the past have been level all the way edge to edge.

In this house both sides of the garages ONLY in the front by the doors have this weird slopping. As you go towards the back of the garage it flattens out.

Any idea why it was done this way? From my understanding my foundation is post tension.

I'm working on putting in a car lift and this is making it a bit complicated.

Pictures make it look a bit more extreme..

<a href="https://ibb.co/qrpRn2R"><img src="https://i.ibb.co/CHQntSn/IMG-2314-2.jpg" alt="IMG-2314-2" border="0"></a>

<a href="https://ibb.co/HGprFpt"><img src="https://i.ibb.co/tYPbmPq/IMG-2315.jpg" alt="IMG-2315" border="0"></a>

<a href="https://ibb.co/PMSKFQG"><img src="https://i.ibb.co/hcqbLfF/IMG-2317.jpg" alt="IMG-2317" border="0"></a>

Stuart in MN · Jun 14, 2019

I assume it was done to make water on the floor drain out the door.

jsimon77 · Jun 14, 2019

I was thinking that as well but I'm in Los Angles...not a lot of water here

Stuart in MN said:
I assume it was done to make water on the floor drain out the door.

BillK · Jun 14, 2019

Probably has something to do with the post tensioning. Needs the extra thickness on the edges ?? Heaven help you if you break one of the tensioning cables. Make sure you know where you are before you drill. The electricians next door have told me a couple of stories about what happens when you drill into one.

jsimon77 · Jun 14, 2019

Yep...So I've been told. I'll have to have an x-ray of the floor, and they will make it off before any drilling happens.

Hilltopmasonry · Jun 14, 2019

jsimon77 said:
I was thinking that as well but I'm in Los Angles...not a lot of water here

Maybe not water but sloped that way in case of a fuel leak?

Sent from my iPhone using Tapatalk

kelpaso1 · Jun 14, 2019

BillK said:
Probably has something to do with the post tensioning. Needs the extra thickness on the edges ?? Heaven help you if you break one of the tensioning cables. Make sure you know where you are before you drill. The electricians next door have told me a couple of stories about what happens when you drill into one.

What does happen?

rsparks64 · Jun 14, 2019

I don’t know, but I do know that my wife won’t let me put our iRobots in the garage.

jsimon77 · Jun 14, 2019

That iRobot is garage only and works really well.

If you drill through a tie in a post tension foundation the thing can explode and come flying up. Under insane pressure I guess.

Radix2 · Jun 15, 2019

jsimon77 said:
I was thinking that as well but I'm in Los Angles...not a lot of water here

But then the mason might not have been from LA.

Or perhaps the previous owner wanted to be able to wash the garage out easily?

Looks like they wanted to slope the floor to the door but keep the edges level.

ConCretin · Jun 15, 2019

kelpaso1 said:
What does happen?

A post tensioned slab has plastic sheathed steel cables running through it in both directions. The cables terminate in a pocket formed into the slab edge, After the slab is placed and reaches a minimum strength, a hydraulic jack is used to apply tension to the cable, which is anchored to a steel block on each end.

If you accidentally cut a cable, the components and patches on the ends will move or even fly out but it’s not generally catastrophic unless you are standing right in front of it. You also lose the cable, which can’t be replaced.

Most catastrophic PT failures i.e. the explosions you see on YouTube occur during the tensioning process when the concrete is still green. These tend to be a lot more dangerous and gave rise to the belief that your garage floor willl explode if you nick a cable in your slab.

It obviously makes sense to be careful and protect the structural integrity of your floor by avoiding the cables but it generally isn’t a life threatening situation.

With regard to the sloping; Does the entire garage slope towards to door? If so, it looks like they kept the perimeter level requiring an abrupt slope to the doors where the two grades come together.

383 · Jun 15, 2019

LLWillysfan said:
With regard to the sloping; Does the entire garage slope towards to door? If so, it looks like they kept the perimeter level requiring an abrupt slope to the doors where the two grades come together.

Here code requires either slope to the door or floor drains. It looks like they sloped the floor to the door, but kept the perimeter level so the stud length wouldn't change to keep the garage level.

EOC_Jason · Jun 15, 2019

All the garages around here (mine included) are like that... Yeah it's a pain, every workbench and free-standing shelves had to be shimmed.

egdede · Jun 15, 2019

Post-tension slabs aren't common in Southern California. You must have unique soil issues for the builder to have gone that route. Though, to be fair, I haven't been involved professionally with any new construction since 1998.

Radix2 · Jun 15, 2019

EOC_Jason said:
All the garages around here (mine included) are like that... Yeah it's a pain, every workbench and free-standing shelves had to be shimmed.

That's interesting, around here they would just run the floor at an angle along the block above the floor that the plates sit on.

I guess we have figured out his mason was an ex-Arkansas man

Git · Jun 16, 2019

I have a post tension slab in S Cal. House was built in 2003 and the garage slab looks nothing like that. The garage floor is about 4" lower than the rest of the house (I think that used to be code) and subsequently, we have a raised 'footer' in the garage that is level with the house slab so the bottom plates of the walls are all on the same level. It almost looks like they poured it in two pours. One for the footer and then the garage floor

Almost looks like they poured your slab in one pour and took a shortcut to slope the concrete down from the side instead of pouring a footer and then the floor

Retroman · Jun 16, 2019

Been in the concrete cutting and core drilling trade for 35+ years, Cut thru and cored thru more cables than I can count. There are the post tension cables in the greased sheaths and there are pretension cable used in precast plank jobs like hotels, motels, malls. I think the risk is greatly exaggerated I certainly do not recommend cutting them due to loss of structural integrity but it is not certain death like most want you to believe most likely thing to happen is the blade or bit is going to be stripped of most if not all of its diamond segments and ruined and you can usally not always feel the slab vibrate when they let go.

Cutting cables was never a big deal in Vegas until a bunch got cut in the top of the Rio hotel during a in house remodel with no permits and the building dept got wind of it that's when things changed around here regarding cables.

Starting a job this week in a major online retailer where we are cutting, removing and pouring back 8,600 sf of 6" thick concrete in the speed lane where the fork lifts run. Has post tension but in only one direction so we will move in 4' from the finish edge and cut the slab and cables to release the tension then move out and score cut the concrete at finish edge. Once the demo is done soil is re scarified we will have a cable guy come in and re-tension and anchor the cables on each edge We then install dowels and rebar and re-pour the concrete. So the new slab section will not have PT cables and the rest of the slab will be re-tensioned.
I have never damaged a cable from roto hammering into one that I know of.

https://www.reviewjournal.com/news/rio-rooms-close/

jsimon77 · Jun 16, 2019

Thanks for all the great info. How do you think putting in a 4 post life will work giving the way the garage floor sloped.

Obviously given that it’s post tension I’ll make the the floor is crated and marked before any drilling.

Anybody ever seen this? Sides of garage heave slot at edges?

jsimon77

Active member

Stuart in MN

Well-known member

jsimon77

Active member

BillK

Well-known member

jsimon77

Active member

Hilltopmasonry

Well-known member

kelpaso1

MEMBER EMERITUS

rsparks64

Well-known member

jsimon77

Active member

Radix2

Well-known member

ConCretin

Well-known member

383

Well-known member

EOC_Jason

Well-known member

egdede

ALLIANCE MEMBER

Radix2

Well-known member

Git

Well-known member

Retroman

Well-known member

jsimon77

Active member