• Jay G.

How to Fix Your Wet Basement (The Best Way)

Updated: May 11

Spring has arrived and it's been raining for weeks. That means wet basement season. Is this the year you fix "the leak"? If so, below I'll show you how to fix your wet basement and make what might seem like a really big job into something that any keen DIYer can do.

Fix your wet basement by digging up your exterior foundation. Clean the foundation and let dry. Apply blueskin and Delta MS membrane. Install 4" perforated drainpipe at the footing attached to an interior sump pump. Layer with gravel and filter cloth. Backfill with gravel and grade earth away from house.

In this article, I'll go through a step by step method for fixing your wet basement. By no means is this the only way. However, if you follow these steps I can virtually guarantee you won't have any more water issues in your basement.

Why Fix Your Foundation?

The answer is obvious, but many people seem to underestimate the severity of a wet basement.

First of all, water in your basement is coming from somewhere. And once it starts, it never gets better. The crack or gap allowing the moisture into your domicile won't magically seal itself, so time is not your friend with a leak.

Second, water will compromise the entire structure of your house. Foundation walls support your whole house, and if one begins to bend, bow, or buckle after years of water infiltration, then your upstairs walls will sag. That means cracking drywall, uneven floors, and possibly roof failure.

Last, you could be creating health hazards for your family. Long term water seepage makes mold and mildew. It usually hides out behind drywall, on foundation walls, on studs and on ceilings in the joist cavities - basically anywhere you can't see.

Don't wait another year to fix your basement water issues - tear up that carpet or other flooring, rip out the soggy insulation or drywall and get to work!

Safety Considerations

Look, if you're going to fix your foundation the right way, then you are either going to need a bunch of friends willing to dig or using a small excavator.

If you are going to go the excavator route, which I highly suggest, then you'll need to be able to operate it safely.

If your yard is too narrow, or on steep inclines, then consider digging out your foundation some other way. Excavators can tip - easily - if you don't know what you're doing.

You can also do some serious damage to your house with a big machine. An acquaintance of mine actually smashed a sliding glass door in his house when he tried to back up and swing the excavator arm at the same time!

Just be careful. You'll also be handling propane torches and using other equipment. Again, if it just doesn't seem safe then don't do it or ask for help.

Will This Work for My House?

If you have a block or poured concrete foundation, then this will definitely help. Will it cure your wet basement? I have no idea! It depends on what is causing your leak.

But if you know water is coming through your wall, and not, say, a basement window, chimney cavity, or other vent cavities, then I'll safely say this wet basement cure will help fix your wet basement.

You also don't need a sump pump to fix your exterior foundation. A sump pump removes water that pools at the base of your foundation via a submersible pump in a pit in a corner of your basement.

It ties into the weeping tile around the perimeter of your foundation and has an outlet pipe that sends the water either into a city storm drain or an outlet in your yard away from your house.

You can fix your foundation without digging a sump pit - I'll cover your other options at the end of this article for how to fix your foundation if you don't have a sump pump. In most cases, it's not a big deal.

Tools You'll Need

Note that this is meant to be a comprehensive list - but you still might need more than what is listed here or you might not use everything I've outlined. Regardless, just know these tools are what I used and they worked.

  • Mini-excavator or lots of friends with shovels

  • Portable propane torch

  • Pressure washer

  • shovel and metal rake

  • Concrete nailer

  • Caulking gun

  • Long-handled paint roller plus lots of rollers

  • Large paint tray for primer

Materials List for Fixing Your Wet Basement

What you need to fix your exterior basement foundation is found below. Note that all products can be found at a local big box home reno store near you, except the gravel. Nearly every locale has several gravel dealers.

How to Fix Your Basement Foundation

OK, time to get down and dirty. This step by step process is for people who have water coming into their basement through their basement wall.

Disclaimer: in no way are we suggesting that this is a definite fix for all basement leaks. However, this step by step process will suffice for the majority of leaks your basement might experience.

Step 1: Make a Plan to Dig

The best way to fix water coming through your basement wall is to stop the water from the outside. That means digging up all the earth immediately surrounding your house, so that your foundation wall is entirely exposed.

You'll need to dig all the way to the footings of your house. If you have a full basement, then you could be digging up to six feet or more.

Now, if you have a deck or a garage then this complicates matters. Many garages are simply on slabs that are part of your overall foundation structure - you'll dig up the earth around the sides.

house foundation walls, digging up a house foundation
Digging up a house foundation

Decks will have to be moved. How in the world do you do that? Well, a couple of ways. One, you could unbolt it from your house, put it on skids, and pull it away from the house with a really serious truck.

Or you could take the deck apart. See my article here for more on how to move a deck.

Call before you dig! Do you have buried electrical, gas, and plumbing? Of course you do!

You've got to call your local dig line, 811 in most places, so a guy from the utility company can come out and spray where your lines are located.

If you have a septic system, then it is your responsibility to know where the outlet and tanks are, as well as your field bed. The last thing you want to do is puncture your sewage line from the house to the septic tank with an excavator.

Not sure where your septic line is? When you bought your house the realtor or previous owners would have provided you with a detailed site map of your septic system, a requirement for home sellers. Check out your paperwork - it'll be there.

Lock block will have to come up, if you have it. Asphalt driveway? That'll have to be dug up, too. IF you have concrete steps, you'll have to remove those, as well. You can possibly do that with the excavator, then pull them away with a truck and heavy-duty rope.

Remember to:

  • Call before you dig

  • Remove all structures within 10 of your house

Step 2: Dig and Expose Your Foundation

Time to dig! As mentioned above, I highly, highly recommend using an excavator for this job. Home Depot, Lowes and many others will rent you a small excavator for a couple hundred dollars a day. They can even deliver it and pick it up for an additional cost.

Excavators and other equipment is typically rented not by day, but by hours. A full "day" of excavator rental is 8 hours. That means when you rent the machine, you get 8 hours of operating time regardless of how long you actually have the machine.

Rent the excavator on a Friday, and that will give you all weekend to use your 8 hours.

Remember, these machines are big but fairly straightforward to use. After about 15 minutes you will get the hang of it, and then it'll be hard to get you off it because it's fun.

Now you are going to dig your foundation. The tricky part is situating the excavator parallel to your foundation so that you can get the arm parallel to maximize your digging. Just go slow and watch out that you don't hit your home.

As you dig, you're going to need a couple of guys, or at least one, in the dug out areas to remove the last bits with a shovel. The excavator can't possibly remove all the dirt. I had two guys helping me, and it wasn't bad.

When you remove material from around your home's foundation, you'll need to put it somewhere. Most people forget about this and end up just putting it right next to their home and just spreading it out.

Fixing wet foundations. Waterproofing foundations. Fixing wet basements. Waterproof.
Digging out foundation around service inlets.

This is a problem for a couple of reasons. First, you aren't going to re-use the material you've dug out.

You are going to fill nearly all of what you've excavated, except maybe the top 12 inches, with gravel.

The earth you remove is not drainage friendly, such as clay, and leaving it near your home may cause water to slope back towards your house.

If you don't have a big yard and can't spread it out and keep your yard graded away from the house, you'll have to get someone to haul it away. A simple "free clean fill" sign at the end of your driveway might get some takers.

You don't have to get every last bit of dirt off the foundation - that's what the pressure washer is for. Also, you'll need at least two feet of room to operate between the earth and your foundation

Remember to:

  • Go Slow with the Excavator

  • Dig all the way to the foundation footing

Clean the Foundation Walls

Now that you've dug everything up, you'll need to clean the walls. This is important for a couple of reasons.

First, you'll be using a product called Blueskin. It's a sticky, asphalt-based membrane that is completely waterproof - and it's awesome. It needs a roll-on primer to stick really well to your foundation, and it won't stick if your wall has dirt or other debris on it.

House Foundation wall, leak proofing walls, waterproof basement walls, waterproof foundation
Cleaning Foundation Footing

Second, your basement wall may have an old coating of tar on it as mine did. This may or may not be a big deal.

The tar on my foundation was really old and dry so removal wasn't bad. Tar must come off before you apply Blueskin, otherwise the membrane will fail.

Now it's time to remove dirt. Get out your pressure washer and make sure you have a long hose because you are going all around your house.

Before you spray, you need to be sure you've dug all the way to the foundation footing. You probably have some sort of old weeping tile at the bottom.

A weeping tile is either a clay, corrugated plastic, or PVC pipe that goes around the bottom of your foundation. It collects groundwater via small holes and diverts it away from your foundation to either a sump pit in your house or to an exterior location further away from your house.

Any old piping should be removed - but only after your spray down your walls! You need to see how that old weeping tile outlets. It should run to a pipe either under your footing into your sump pit on the interior of your basement, to the city storm drain, or a daylight drain that empties elsewhere below the grade of your house.

When you spray down your walls, you'll have tons of water at the base of your foundation that needs to go somewhere and your old weeping system should be there to collect and divert it.

If you are concerned about getting water in your basement from the power washer, don't be. Unless you focus the spray on the offending crack or hole, water won't get inside.

Remember, leaks in your basement typically are gradual and over time. A quick spray from a power washer will not cause a leak. It doesn't take long for a washer to dislodge dirt from a wall.

Use a torch to dry off the wall completely and get rid of any other substances. You want a clean canvas for the Blueskin.

Lastly, you should clean all the way down the top of the footings. You'll be applying Blueskin over this area as well, so it should be clean. Water is going to pool, but your old drainage system should remove the water as you go.

Remember to:

  • Leave the drainage system intact until after you wash

  • Resist the urge to blast your wall - only a light-duty clean is necessary

Remove Old Tar

Nearly everyone waterproofing basement walls from the outside will encounter an old method of waterproofing. If not, then it's no wonder you had water in your basement!

Usually, it will be tar, because back in the day that was considered the best way to waterproof your basement. Blueskin and flaky, old tar are not friends. It has to go if you want proper adhesion of your membrane.

The tar on my house was really dry - which means it was old . I ended up scraping it with an ice chopper. Other options were muriatic acid or that purple cleaner stuff.

Once I got all the dried stuff, I felt the torch method was simplest method to get everything dry. After testing out a small patch with my portable torch it was clear a large torch would do the job. It makes the job much much faster. Can't recommend this enough.

So I rented an industrial-grade propane torch from Home Depot. It needed an air compressor which I already had, but if you don't have one you'll need that too.

You'll also need propane, which you can hook up to the propane tank under your barbeque. Just note that you'll likely need more than one canister.

I went around the foundation slowly and dried everything. I had a clean surface for my primer. Just be ready to have patience. However, if you get a friend to use the torch, then you can work behind them applying the primer.

A third and fourth person is great to apply the Blueskin. This way you can move faster and reduce the risk of debris getting into your primer. You'll need more than one person to apply Blueskin.

Old oily tar that won't come off accepts the primer just fine, and is OK to leave beneath the new Blueskin.

Remember to:

  • Scrape away all old bits of tar, all the way to the footing

  • Use a torch to remove moisture and speed up the process

Apply Blueskin Primer and Blueskin

Applying primer is best done using a roller with an extended handle. Be ready to use a lot of primer, because the roller really soaks it up. Don't skimp, though, because you want precision adhesion for your membrane.

Take special care to apply primer around openings for plumbing or electrical, where water loves to penetrate.

Don't apply primer to the entire foundation and then apply the Blueskin. Do one section at a time, then apply the membrane. Applying Blueskin membrane without primer is a recipe for failure - always use the primer!

Overlap the sections of Blueskin membrane by at least an inch. If you have an upper section and a bottom section, make sure the piece above (closer to ground level) overlaps the bottom piece, not vice-versa.

Everyone will have a different amount of foundation to cover. Mine ended up being about 6 feet from the footing to ground level.

Your Blueskin should come all the way up to ground level - but you never want to leave Blueskin exposed to UV for long. If any water happens to pool around your foundation, then it will contact the Blueskin first.

Be sure to Blueskin all the way down to the footing, and onto the flat, horizontal part the juts out from your vertical wall. This is crucial because lots of water gets in your basement between the footing and block or poured walls.

Put the membrane as far down the footing as you can. I was able to get it almost on the entire flat part of the footing - if it's too dirty, then at least cover the joint between the footing and walls.

Fixing leaky basements. Waterproofing basements. Fix leaky foundations.
Applying membrane over foundation walls.

Some people will tell you to add a "bevel" of concrete along the joint between the footing and walls for added water tightness.

I didn't do that for two reasons: time and I didn't think it would work. I had way more faith in the Blueskin to do that job, and so far I've been right.

Important: More than likely you'll encounter either a ground wire, piece of plumbing, electrical, septic or city wastewater outlet - this is called service penetration.

Putting Blueskin around these penetrations properly is critical. Here's what to do:

  1. Prime all around the penetration

  2. Cut a square of Blueskin that will cover all around the area the penetration

  3. Make a horizontal cut across the middle of your square - use a sharp exacto knife

  4. Place the square over the penetration

  5. Cut smaller strips of membrane to fit over the service penetration so that at least a few inches of the protrusion is covered. Start away from the wall and work toward the wall, so the pieces closest to the wall overlap the pieces that are further away.

Once you cover up your service penetration, continue with your Blueskin. When you encounter a service penetration, you'll do the above method.

Then, with your big roll, you'll have to end the layer exactly at the penetration. Cut a horizontal cut in your next layer at least 6" where the penetration is, and apply the layer.

In this way, you'll have a couple of layers of Blueskin over your penetration, plus the extra small strips you put on for extra protection.

Careful! Blueskin is sticky - very sticky! You'll need two people to unpeel and stick - a third is even better because two people can hold the membrane taut while the third adheres it to the cannot do this step yourself!

Remember to:

  • Apply primer and membrane as you go - don't prime the whole foundation first. The primer is critical to proper adhesion.

  • Take care covering wire and pipe protrusions - most leaks occur there

Install Delta Membrane

This was the easiest part of the job. Delta membrane comes in giant rolls. It is the primary barrier between your basement and moisture. It sits against your Blueskin and covers the same area as your Blueskin membrane, going all the way to just above ground level and slightly above the Blueskin.

When I applied the Delta, I started in the middle of my longest wall. Delta comes with specific fasteners to keep the membrane in place, and you absolutely need them. You'll also need the mold strip, delta sealant, and regular concrete screws.

The membrane came in rolls that were 6' high. That was perfect, as it was just enough to cover the Blueskin, the footing, and go just above the Blueskin at ground level.

I used the top of the Blueskin as a level for the membrane. It installs with the orange strip facing towards you, and the smooth edge of the Delta at the top of your foundation wall. The mold strip goes over this smooth part.

Starting can be a bit awkward. If you don't have the top of a Blueskin membrane to follow as a guide, then you'll need a chalk line. You can't eyeball this because the membrane must be flat and level against the wall otherwise you compromise the entire process.

Have a friend hold the end of the membrane as you roll it. If you don't have a friend, drive a nail through the plastic delta fastener to hold it in place. You'll have to drive two nails to keep it level. I used a Ramset semi-automatic that I borrowed from a friend - it worked like a dream.

The Delta specifies that each fastener is placed about 2' apart. I roughly held to this only because it made installation way easier as it kept the membrane tight and level to the foundation.

Pull the membrane tight - gently! - around corners. Don't use the fasteners too close to the corners for risk of chipping. I only had outside corners, so wrapping around the flat part of the footing on the outside corner was awkward.

I put one diagonal cut going out from the bottom of the outside corner where the footing meets the wall. The two pieces of membrane then overlapped and I just put a bunch of sealant down there to connect the diagonal cuts, one on top of the other.

When you get to your service penetration, you'll have to cut your piece of membrane entirely and start a new piece. Cut your piece so that it is flush up against the penetration. Put a couple of fasteners along the vertical cut to keep it in place.

Start a new piece 6" overlapping your cut piece. Make a horizontal cut on your new piece of membrane that is level with the penetration and pull it over the penetration tight.

Now peel back the new piece of membrane and absolutely saturate the entire area around the penetration - and the whole vertical joint - with sealant and press it firm.

Use fasteners up and down the entire joint every 12" or so. I contemplated using this method with the Blueskin, but cutting new pieces of Blueskin is pretty damned infuriating, so I opted for the method I stated in the previous step.

When you run out of length and have to start a new roll - I only used 2 - then do the same process as you did when you had a service protrusion.

Overlap by 6", install a couple of fasteners to hold the end of the membrane in place. Then install the new membrane, seal the entire joint and use fasteners 12" apart vertically.

Remember to:

  • Make sure Delta membrane overlaps the footing

  • Seal all vertical and horizontal joints between membrane with sealant

Apply Delta Mold Strip, Sealant, and Nails

Now that you've got your Delta membrane in place, it's time to seal the top of it. Get your caulking gun out and load up the delta sealant. You are going to seal behind the smooth, top strip of the Delta membrane around the entirety of the house.

I did the whole house first, then came back to install the mold strip. The mold strip is fairly straightforward. The wide edge of the strip goes over the top of the membrane. This is where the fasteners go.

For the strip, I used my Ramset without the plastic Delta fasteners. I used 1.5" nails as suggested by the instructions. They worked fine. I placed them about 8" apart.

Remember to:

  • Apply sealant behind the entire flat part of the membrane that contacts your foundation wall - above the Blueskin

  • Don't bury your concrete screws too far into your concrete

Install Your Weeping Tile

Weeping tile is actually just black corrugated plastic pipe with a bunch of slits cut into the entire length. It also has a white, permeable sock over it to keep out debris such as rocks and dirt. You can buy it at any home reno store in 50' foot coils.

Called a 'weeper', this will sit at the bottom of your footing where the Delta membrane terminates. I was able to put it against the vertical face of my footing.

Before you lay the weeper, put down a small layer of gravel. You should only put enough for the weeper to sit on, as you want the weeper up against your footing. If the weeper sits any higher you risk water penetration at the base of your foundation wall.

Next, I connected the weeper to my sump pit. Before I did this I made sure to clear out the drainpipe connecting the weeper and sump pit.

I used a garden hose and blasted through a good deal of muck. This sent all of the debris into my sump pit, which my sump pump took care of, but be careful. Sending a bunch of debris and water into your sump pit at once could cause your sump pump to clog - so do this at your own risk.

Next, connect your drain pipe to your weeper. I had an old plastic drain pipe that was 2" in diameter. I was able to find a connector that would fit with the weeper.

I didn't connect either end of my weeper, but I made sure either end was flush up against one another. Both ends had socks over them, so I figured there wasn't much of a chance of debris getting through.

Remember to:

  • Lay gravel beneath your weeping tile

  • Take the time to clean out your sump system - you might never get another chance

Backfill with Gravel and Install Filter Cloth

You're almost done. Time to use your mini-excavator again. I had two different piles of gravel.

For the bottom, right on top of the weeper, I purchased a half-ton of 3/4" clean gravel. This is a bit smaller than your typical driveway gravel. I wanted the finer stone closer to the foundation for better filtration.

Waterproofing foundation. French drain. Fix leaky basements.
3/4 gravel immediately over weeper (french drain).

I laid this evenly so that it covered the weeper around the whole house, about 6" above the weeper.

Then I installed filter cloth above the 3/4 gravel. This is to filter out any remaining sediment on it's way to the weeper. It will keep the weeper from clogging.

Then I backfilled the rest of the foundation with regular 1" gravel. I was able to use the blade of the mini excavator to push the gravel into place.

The gravel I purchased - 2 tons - turned out to not be quite enough. I ended up having about a foot and a half around the entire perimeter left to fill.

I used the material I dug out to fill the remaining space. Most of that material was gravel anyway, but with dirt mixed in.

Even if you have enough gravel to backfill your entire foundation, you'll want to keep about a foot or 6" left to backfill with soil. This allows you to grade the earth away from your house and gives water a clean ramp to run off into your yard.

Waterproof basement foundation. Fix leaky basements.
Filter cloth over french drain and 3/4 gravel.

If you choose to backfill gravel all the way to the top then all rain and moisture would flow straight down to your weeper instead of staying on the surface and into your yard.

The soil provides more of an impermeable surface than gravel. Either way you've created an impermeable membrane, but leaving some soil on top is better.

Remember to:

  • Backfill slowly to avoid damaging your membranes

  • Have enough gravel to fill what you've excavated

Grade Soil Away from Your House

The most important part of this whole process is grading your dirt away from your house - called the crown.

Use a metal rake to grade the earth down and away from your house. Even if your house sits in a depression, you can still grade the earth next to your house away from the foundation.

Even if the earth then moves back uphill, having a downhill grade immediately next to your foundation prevents pooling against your foundation walls. Pooling even 12" away from your foundation is much, much better than pooling against your walls.

I left the top of the molding strip of the delta membrane uncovered. Over time I've noticed that the sun has damaged it somewhat, and I'm wondering if I should've covered it up. However, the membrane top it is covering still seems to be perfectly fine.

Remember to:

  • Grade earth away from your foundation

  • Have a plan for removing excess material

Final Thoughts

I hope you found this article helpful. As always, work safe and work with a friend or two. Prepare all your materials beforehand, make a plan, and you can do this job on a weekend if you have some nice weather.

This was my experience repairing the foundation of my house. If you still aren't sure this is a job you can pull off alone, then call a professional. On the other hand, this is a job a handy person can do - and it will save you tons of money.

Thanks everyone - please leave a comment below or drop us a line for any helpful tips or suggestions you might have for us. Check out Dry Foundations on Facebook and Twitter for more helpful articles.


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