How to re-grade concrete on a budget?

September 3, 2024 10:17 PM

One side of our concrete driveway has sunk and it now slopes toward the house. This is causing water to run off toward the house and into the crawlspace, and it's causing water damage to the sub-floor framing. Are there any inexpensive ways to fix the grading of the concrete, even just for one winter?

Whatever we do needs to run for 30 feet along the length of the driveway. I think it has sunk by an inch or two.

Are there any options for sending the water in a different direction, besides mud-jacking to raise the slab or taking out the concrete and having a new slab poured? I know raising or replacing the slab are the correct solutions, but they're not in the budget. Hence the search for creative/alternative solutions. I'm fairly handy, but I don't have a good sense of what will or won't work for this.

Other factors that might be relevant:
- The house was built in the 1930s.
- The stucco siding extends below grade (not ideal, I know).
- This is a "driveway" but we drive cars over it rarely, if at all.
- It would be nice if we could walk and put things on whatever surface ends up there.
- We're in an area with expansive soils.
- We get a rainy season and a dry season. The rains are coming.

posted by Mirth to Home & Garden (9 answers total)

P.S.: I'll probably ask about the sub-floor framing situation another time. For now, I'm just trying to make sure it doesn't get worse.
posted by Mirth at 10:20 PM on September 3

If it's only temporary for a season or two while you figure out and finance the long-term solution, would something like long-line sandbags work? They're not pretty, but infinitely less expensive than an increasingly sunken foundation.

I may be off-base, but the description of your house, seasons, driveway, and soil makes me think you might be in southern California. If you're in the LA area, I highly recommend Alpha Structural to at least do an assessment so you can get an idea what you might be looking at. My coworker recommended them to me and they're awesome, so I'm passing on the recommendation just in case.
posted by erst at 10:32 PM on September 3

You could DIY a cold asphalt berm along the sunken edge. It also won't be pretty and it won't last forever.
posted by qxntpqbbbqxl at 10:35 PM on September 3

Raising that side of the slab may not cost as much as you think.

There are companies around here (PNW) that will inject expanding polymeric foam directly into the ground to raise and level concrete, and I’ve heard that they are much less expensive than more traditional approaches.
posted by jamjam at 11:03 PM on September 3

I used to do insitu concrete repairs and in short-term cases I agree with qxntpqbbbqxl's suggestion, either asphalt or even a homemade cement (sand + not too much cement so can remove later) berm - in case asphalt hard to obtain. It'd be helpful to know your State (your wording suggests the US).

Yes foam-jacking is cheaper than mud. The subsidence does need resolving for certain.

If the drop is two inches that makes a surface repair easier, if an inch only it gets difficult to get a bond.
posted by unearthed at 2:39 AM on September 4

I'd agree with a concrete or mortar berm, talk to a person at a good hardware store about what bonding agents could be added to it to get it to stick to the sunken driveway. Then it's a day of yakka, if you've never done it before it'll look ordinary but it'll work for a couple of years.
posted by deadwax at 3:53 AM on September 4

If the edge is in fairly good shape (not too cracked) I would be tempted to use construction adhesive (as caulking underneath) and a few concrete screws to glue down 30' of pressure treated 2x4 to create a temporary curb. This will route the flowing water away from the house. It will last for a few years and be easy enough to pry up when you redo the slab for reals. Or to pry up and replace with the same thing again when it starts to leak.

This will look less shitty than sandbags, and probably cost less and be less messy to install than concrete or asphalt.

3 @ 2x4x10' PT, couple tubes of construction adhesive (go nuts with this), box of 3.5" tapcons to hold the wood down while the adhesive dries. Clean the concrete thoroughly (brush, hose off, allow to dry) where you'll glue the wood down. Set the wood in place, pre-drill three holes all the way through each board to score the concrete, drill the concrete where the holes were marked, vacuum up the dust, run the Tapcons through the wood till the tip is exposed half an inch register in the holes, goop up the bottom of the wood with construction adhesive, set the wood in place, lock the screws down. (You could use blue steel concrete spikes and avoid all the pre-drilling but there's a risk of splitting the concrete that close to the edge.)

Feel free to add another course of 2x4s on top if you feel there will be a LOT of water running down, but even a 1.5" curb should redirect even fairly heavy rainfall somewhere else.
posted by seanmpuckett at 5:54 AM on September 4

In a similar situation we used Quick Dam flood barriers which are like sandbags but are full of synthetic goop that expands on contact with water. They come in different sizes, you could get 3-4 of the 10 foot long ones and overlap them to cover the length. The benefit is they require no tools or thinking, and they are not heavy - they ship dry so they're like a long dry fabric tube. You can get them in an easy package from Amazon or Home Depot etc and can deploy them immediately (lay them out dry and then wet them to expand the goop). Then they can just sit there for the season until you figure out your real next steps.
posted by LobsterMitten at 7:08 AM on September 4

We used self leveling floor cement , one pour over another building up very smooth swath filling in the low place 1,1/2 , the edge about 1/4 inch thick hasn't lifted this gypsum based cement is sticky, but smooth. I didn't expect it to last 5 years ago, still fine today
posted by hortense at 2:22 PM on September 4