Steep Driveway; Lowering Garage Floor

Does anyone have any experience with having their garage floor lowered? Our house was built in 1959 and we have an extremely steep driveway - it would not meet building codes if it was built today. Also the garage floor is sloped a little bit towards the driveway and the garage floor is extremely rough concrete. So between the slope and rough floor, it is tough to wheel large tools around. We are in the midst of renovating all the landscaping and masonry work in the front of the house (also a very steep slope) and the landscape architect has made the suggestion of lowering of the slope of the driveway by lowering the garage floor about 2 feet. We do not have the final plans and cost estimate yet, but I figure between 30-50k+ just for that part of the overall project. This would involve many aspects... moving all the machinery, jack hammering the old floor, digging, supporting the foundation walls and pouring new footings, a new driveway, new garage door, loads of permits, and the town will likely require consultation with a structural engineer, etc... But in the end the slope would be reduced and I could have a smooth, level garage floor with extra tall ceilings - great for storage!

SB

I don't have any experience with this, but tall ceilings and a nice floor would be super. I doubt you would end up getting the money back when you sell. If you plan to stay for a long time, it could very well be worth the cost.

I would guess that your costs are going to be very high as "supporting the foundation walls and pouring new footings" under an existing structure won't be easy or cheap. You might need to put a one at the front end of your estimate. Make sure your engineer and contractor know what they are doing and you may need permits for all this work.

Sounds like a great idea. The thing I would pay very close attention to is the drainage. When my now architect son was interviewing schools one dean told him much design effort and most of the lawsuits are concerned with keeping water out of the building.

When the government built the secret city of Oak Ridge in a big hurry in the early 40's most if not all of the houses were built over crawl spaces. After the war these houses went into private ownership. Over the next decades a LOT of people dug out basements to expand their houses, doing essentially what you plan, but digging down maybe 4 to 8 ft and putting in block walls and concrete floors. I know a guy who rented a bobcat to dig his but others did it with hand tools and a wheelbarrow. I've been in a number of these retrofitted basements and some are beautifully comfortable with carpeting and wood paneling. Others have had water seepage with wet floors and constant mildew. Much of Oak Ridge is built on, well, a ridge, and the sides of the hills.

Not as likely on a hill but still possible if any part of the target depth is below the current grade: you don't want find out later you dug into a seasonal water table. A geologist friend did some consulting for a new homeowner with just that problem - when they built the house everything was perfect but discovered a real problem during the first wet season.

For your project it may be as simple as jacking up the structure, digging down and laying good drainage around and maybe under the structure. Consulting the professionals seems wise.

JKJ

Thanks for the tips. If we take this on it will be for us to use and enjoy; we would not do the change in the garage floor with the intent of getting our money back. The area in which we live is very highly regulated in terms of licensing of contractors and permit requirements. Our initial exploration of the idea is with our landscape architect, and he is bringing in an engineer to look at the drainage situation. We are also going to have a structural engineer look at the existing structure and foundation walls. The permit will require all plans to be signed off by licensed architects and/or engineers - whichever is appropriate. Even dropping the floor by 2 feet would help the driveway situation quite a bit. I could do a nice commercial epoxy floor or perhaps polished concrete.

SB

If you decide against lowering the floor put in a wood floor that you can level. PT 2x4s flat with hard foam insulation in between. Cover with plastic and put down your flooring of choice.

The challenge might be relative to how the foundation under the garage walls is constructed...codes may have been different "back then" and there may not be much to work with relative to lowering things. It does sound like a reasonable project idea, however, if the "little things" can be worked out.

Is their a public sidewalk involved? I have seen houses where the sidewalk is on a narrow bridge over the driveway into the below ground garage. If there is a sidewalk the slope on either side will have to be ADA or less.
Bill

You must have already thought of this, but there any chance that your lot is large enough so you could re-route the driveway, i.e. plateau & curves to reduce the grade?

In the area of the country I live in, most attached garages are built with stem walls, and floating floors. This type of construction would not be nearly as difficult to lower the floor as what you describe. Seems it would be much more simple to just sell your existing house and buy one with less slope on the drive.

Quote:

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Originally Posted by Jim Andrew

...Seems it would be much more simple to just sell your existing house and buy one with less slope on the drive.

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Ha! Not having a steep driveway was one of my requirements when we looked for property for a farm. My wife searched for five years for a place and I'd say 3/4ths of the properties for sale around here were on the side of a hill and had steep driveways. Maybe these places were for sale because the owner got tired of the driveway (or didn't have a good place to build a shop!)

She finally found this place, lots of woods and fields, land gently rolling, timber frame house, old barn, outbuildings (and a great place to build a shop!) But the property was so grown up with briars and such it looked awful and not one person had made an offer in the year it was on the market. Cleaning up land is not a problem.

JKJ

What country do you live in?
Bill D.
USA

I used to build houses, and before I was done put in 3 subdivisions, and sold building lots as well as built on a few of the lots. Once I sold a lot to a lady, and the street went down hill to the north, and also downhill to the west, and this was a corner lot. I told her to put the garage on the south, as she could keep the driveway slope low, and the slope of the lot would allow her to put daylight windows on the west side. So, she put the garage on the north end, steep drive, and they filled the west side and put in no daylight windows, and then she sat on the house for 3 years.

I think I'd solve the problem by selling the house and finding one more suitable, would be a better solution. Lowering the garage 2' is likely going to affect the house foundation under the garage walls. They don't build them much deeper than that in many parts of the country, but I have no idea where you are located.

Charley

The house was built in '59. If it's a detached garage, it would almost certainly be much cheaper to take it down completely and rebuild. Why? Because '59 puts it in the lead paint/asbestos era, and any "remodeling" would almost certainly require full blown EPA mandated remediation, which will be expensive. If it's attached, find out BEFORE you start whether or not you're going to have to remediate, and proceed accordingly.

It may make sense to jack up the garage an inch then demolish the floor and footings. Build a new floor and footings and extend the walls. The extensions can be wood above grade but will have to be concrete or block below grade. This should be faster and cheaper than trying to save something.

The permit process will tell you what you can and can’t do. In my case I built a workshop/garage building. The building code required the garage section to have a sloped floor whereas in my workshop without a garage door the code allowed a flat floor. I also remember we had to redesign the foundation because a building code change that wasn’t caught by the designer. The code will determine what you can and can’t do as intrepted by those granting the permit(s) not your landscape architect.

Sell it and move like recommended above.

What kind of shape is the garage in? Insulated? Updated wiring? I like the idea of lowering the driveway and garage floor, but I would consider at least taring the garage down (unless it is under a portion of the house) and rebuilding the whole thing from the ground up. A bit more money, but a whole lot easier. Plus you can get exactly what you want.

I would want to look a bit deeper before recommending a sell. Selling will cost 10% or move of the value of the house (6-7% sales commissions, concessions to the buyer, moving costs, points on new loan origination). Say he has a $500K house, that's $50 flushed down the toilet. Also it sounds like the existing driveway detracts from the value of the house. Would the new lower drive increase the homes value? Now, says the house is worth $200K, probably never make sense to spend what it would take to lower the garage floor and drive.

$50k is a lot of money to end up with the same square footage. Is there room to build a separate shop and just live with the driveway?

If you have to dig it out anyway why stop at two feet? Dig down deeper and have a basement for the ducting and storage with a shop on top.
Bill

Just a few thoughts... Put a second floor in the garage and move the walls in so not to disturb the house foundation. Lay new walls from the new floor up to the house. Bu putting in a second floor should really drop the driveway down.