Basement Waterproofing Tips

Basement leaks are easy to prevent and even fix without taking a bath

In the 20 years I spent as a professional home inspector, the top three problems my home-buying clients were concerned about can best be summed up this way:  water, water and water!  Waterproofing your home is the surest way to make sure buyers stay interested.

While leaks through roofs, pipes and basements are constant concerns, a wet, leaking basement always ranked highest as the home improvement problem most likely to send buyers running for the nearest open house. 

Whether you are a buyer, seller or owner of a home, wet basements are always a concern. Not only is a wet basement unusable, flooded foundations can be seriously weakened and toxic mold--the newest threat to residential indoor air quality--can fester faster when an ample supply of water lies just underfoot.

3 steps to stop a wet basement

The good news about these unplanned indoor pools is this: while wet basements are often thought of as one of life's biggest home repair headaches, they are generally easy and inexpensive to fix. Yes, that's right--easy and inexpensive!

The wrong way to waterproof a wet basement.  Ask 10 people how to fix a wet basement and you're likely to get answers that include use of jackhammers to break up basement floors, backhoes to dig out dirt from foundation walls, sump pumps that have to be wired and plumbed, and other such drastic and expensive measures.

While these solutions may seem to make sense, they all attempt the impossible: to seal a foundation so tightly that it will somehow hold off water like a boat. Well, unless your house is a house boat, it won't float, so you might as well stop thinking about all the ways to keep it from doing that.

Most people blame a wet basement on a high water table, the natural level of water in the soil under the building site. This is another myth, because homes are not built below water tables. Builders attempting such a feat would find themselves constructing a foundation in a muddy mess. Likewise, basements that flood after a storm are never caused by rising water tables. A water table moves slowly and seasonally. If basement leaks show up after a heavy rainfall or snowmelt, the cause of your problem is far easier to spot and to fix.

Most basement leaks can be traced to trouble with the drainage conditions around the outside of the house. If  too much water is allowed to collect in the soil around the foundation, it will naturally leak into the basement through the walls, or even up through the center of the floor.

The waterproofing solution lies in improving these drainage conditions, which is easy, cheap and highly effective. Here's where to begin...

Good gutters.  Roof drainage is, by far, the number one cause of basement leakage. Since roof surfaces are as large as the house, they collect lots of water in heavy rainstorms. What happens to that collected water can mean the difference between a wet and a dry basement.

Properly designed gutters should have at least one downspout for every 600 to 800 square feet of roof surface. Gutters must be clean, because dirty gutters fill up and the water overflows directly to where you don't want it: near the foundation. It's also important to make sure the ends of the downspouts are extended to discharge at least four to six feet from the foundation. Spouts which discharge too close to the foundation are like big fire hoses blasting water into the basement.

If your yard and local building laws permit, one of the best ways to control roof drainage is to discharge downspouts into solid PVC plumbing pipes that run underground and release water to the street or to another low-lying area. When making this improvement, be sure to pitch the pipe slightly toward the discharge point to avoid backups. Also, don't attempt this with the soft, flexible black pipe that landscapers like to use around flower beds, because it's easily crushed and cannot be snaked clean like PVC plumbing pipe can.

Sloping soil.  Next to gutter problems, the angle of the soil around the foundation perimeter can also cause wet basement woes. The soil should slope away from the house to keep rainfall from collecting against foundation walls.

The angle and type of soil are also important. The soil should slope downward six inches over the first four feet from the foundation wall. Thereafter, it can be graded more gradually but should never allow water to run back toward the house.

If grading needs improvement, use clean fill dirt (not topsoil) to build up the soil around your house. Tamp the soil down to the correct slope and finish with a layer of topsoil and grass seed to prevent erosion. Or, just use stone or mulch. Whatever the top layer is, be certain the slope is established with the fill dirt, or else the water will just run through the more porous material and into the basement. Also, don't use straight topsoil for the grading improvement. This kind of soil is too organic and will hold water against the foundation, which is the opposite of what needs to be done.

It is also important to avoid landscape treatments that hold soil close to the house. A brick, stone or timber landscape edging around flower beds adjacent to foundation walls may look attractive, but these edges can prevent water from draining away from the foundation and increase your risk of basement flooding.

Following these simple guidelines will solve 99 percent of wet basement blues. These waterproofing improvements are inexpensive and can usually be done yourself or with a little help from your friends.

Avoid panic-peddling waterproofing contractors.  If you've ever thought about hiring a so-called waterproofing contractor to fix your wet basement, don't. Basement waterproofing contractors can often be rip-off artists that attempt to scare homeowners into an expensive drainage system when they're usually not needed.

Several years ago, one of my home inspection clients attempted to fix his leaky basement by calling in waterproofing contractors. Besides telling him his foundation would crumble without a waterproofing system, they offered quotes ranging from $7,500 to $20,000. These were outrageous expenses, even if the system did need to be installed,which it didn't.

Instead, following an inspection, we were able to instruct him on how to correct his outside drainage and easily fix the wet basement problem for under $500--and he avoided getting the soaking of a lifetime from a waterproofing contractor! 

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basement waterproofing

Over 35 years in this business, my experiences have been 'most' waterproofing companies are incompetent and pretty often fraudulent. Most of those are the interior drainage system companies.

The interior system companies almost always do not honestly and competently 'identify' aka, find, determine the homeowners actual-problem(s) or don't care to. All they are interested in is saying whatever they need to, to homeowners, in order to sell the one thing they do.

Many homeowners only have 1 or 2 areas in basement where they leak, seep, get water in on floor...usually along the bottom of wall/floor aka, the cold joint, cove.

And most often, the reason(s) they get water in there is due to cracks in the basement wall, exterior cracks or exterior cracks in the parging or no parging was ever applied to exterior of some block, brick walls. And rod holes in poured walls are often the problem, reason, not the grade, this is a myth.

Other reasons for wet, leaky basements include one or more exterior openings, gaps above grade such as open, cracked mortar joints, openings around basement windows, doors etc. And some homeowners get water in, on basement floor due to a possible blockage in lateral line, clean out or the city has problem on their-end. Sometimes the drain tile that leads to/from sump pit needs to be snaked etc.

Way too many people offer advice, supposed-fixes, and they are not experts on the subject.I don't ever offer any supposed advice/supposed remedies on anything else because, lol, I'm not an expert on anything else! Not hvac, not electrical etc yet, again, many offer supposed solutions on this-subject and they are not experts on this subject, got it? lol

Why 'go there'? Being a good, honest home inspector or builder or landscaper etc does not at all make anyone an expert on this subject, sheesh

Basement Waterproofing Contractors

I have go on record here and state that while I realize there are some predators out there, just because waterproofing jobs are expensive doesn't mean they're a rip off. Yes, revising the exterior drainage of the home may prevent further damage from being done, however it does nothing to address the damage that's already been done to the foundation or the soil around it. Better advice would be to seek out a contractor that is certified and follows a specific code of conduct. To say that we're all crooks is inaccurate and very misleading.

basement waterproofing cont'd. sorry a bit long

Have seen many homeowners (have photos) who already tried raising and sloping their grade, still leaked and called me.

Some of those were builders own homes and some dug down about 2' along wall where they leaked and poured concrete along, against basement wall and then raised and sloped the grade above the concrete, still leaked Tom!

Others have down down 1-2' (where they were leaking) and then layed shingles all along, against the basement wall and then raised and sloped the grade, still leaked Tom.

And still other homeowners dug down 1-2' and placed several tarps along, against basement wall, where they were leaking AND raised and sloped the grade, still leaked.

Say again, other than basement back ups (most often a city problem or lateral line),most homeowners get water in basements because they have 1 or more cracks in basement wall or, 1+ open, leaky rod holes.

Tom, cracks are existing defects. Would you recommend selling a house that has 1+ cracks in foundation wall that have allowed water in basement and that haven't been waterproofed?

When there are open mortar joints or cracked joints, bricks above grade...they need to be tuckpointed, sealed right? Because if they're left open they will allow water into home,possibly cause mold, allow easy access for termires etc. You wouldn't tell homeowners to leave them open, would you? lolol

If water is entering someones home through, around windows or doors, would you leave these open, not caulk etc them?

Well, same applies to basement walls that have a crack or leaky rod hole man.

And toying with the grade or gutters has not 'identified' the actual existing problem, defect and of course does not fix, repair, waterproof, tuckpoint whatever the real-problem turns out to be.

One needs to fisrt, FIND aka identify the actual problem so that they can then, fix it correctly!

Your assumption that 99% of wet, leaky basements can be cured by playing with the grade is absolutely incorrect sir. And in order to help more homeowners and give them the facts then sometimes we need to change our tune, admit we made a mistake.

basement waterproofing

All due respect man but,, you are wrong sir.
If you really want to help most homeowners on this-subject you'll listen and want to understand more, I've tried sending you photos etc but maybe your too busy or just assume you know all on this subject.

There's no way on this-planet that 99% of homeowners, as you say, can solve their leaky, wet basements by toying with the grade, nope.

I'll agree with you that many more companies in this business than not are either incompetent, fraudulent, misleading, deceptive and so on and those are just about all 'interior system companies'. Yes, those inside basement drainage companies misrepresent this subject in a big way.

Ok so let's say a homeowner has a leaky basement, its finished/drywall and they get water along the wall-floor aka cove in 1 or 2 places. Some homeowners simply are getting water in due to 1+ leaky, open rod holes.

Other homeowners egt water along same area, cove, due to a clog in their lateral line, they simply need it snaked by an honest plumber.

Other homeowners get water in, that can run down poured wall behind drywall....through 1 or more exterior openings around,above,in a basement window or around door, or 1+ open mortar joints or where a service line enters a house above grade.

So telling these homeowners to play with the grade doesn't, hasn't correctly identified their problem and won't fix it, they'll still leak Tom because, as I said, if their problem (where water is entering) is openings around, in basement window or open mortar joints then raising and sloping the grade cannot tuckpoint the open mortar joints, doesn't replace that leaky basement window!

Same goes for cracks say, on the outside of blck basement walls, Have many photos to show you exactly what I mean in order to, help homeowners!

Waterproofing your basement

This is an excellent article with a lot of really good points and suggestions. However, I think it's important to note that it is okay to consult with a basement waterproofing expert should the need arise.

But make sure to check your drainage first; since your waterproofing issue could be a simple fix!

If your basement commonly experiences flooding or puddles, or you notice cracks in the wall or floor; it's probably time to consult with a professional.

Everyone is an "expert," so make sure to do a little bit of homework before accepting a quote or estimate.

Check licenses and reviews on the BBB or Home Adviser. A reputable waterproofing contractor will also be more than happy to provide you with these things in addition to the phone numbers of past clients. After all, waterproofing your home is a big deal. You want to make sure it's done correctly. And a good company will understand.

Also make sure to get several estimates. And don't be fooled into the lowest priced option. Cheaper isn't always better. Make sure that the company has been around for awhile, is licensed and insured, and offers you warranties for the installed waterproofing solutions.

Basement Waterproofing

This article makes some very good points. As one of the largest basement waterproofing companies in the country, I don't necessarily agree that 99% of all wet basements can be cured by following your tips. But, we are all for proactive homeowner maintenance and water management. I'd also argue that most basement waterproofers are ripoff artists. There's definitely a fair share of them, but many good ones too.

Water in Basement

Tom, thanks for commenting. Grading the yard with proper soil and extending my downspouts would not of fixed my problem. I agree that it is a good first fix. But there are water issues other then surface water. I understand that by digging around my foundation, I disturbed compacted soil, creating no resistance for the water so it fills my hole very easily. But the fact is that I have no rainfall whatsoever getting in my hole. My land is graded very well now, due to the huge mounds of soil from my hole. Plastic covering my entire hole. All downspouts extend pretty far. So where is the water coming from? So you said it yourself. Higher elevation water flowing to lower elevation. I do not know exact terms of hydrogeology(just looked that word up). I just know that I have a underground water problem. At high rains my water rises from the ground. I can visually see this. Water forces its way to the top from the bottom of my hole. It creates little rivets in the water. All the other websites talk about rising water tables also. Not just websites that are trying to get your money. Your website was the only one that stated water tables rising as a myth. That is my only issue. Water tables rising are a concern. People do build below them. I would still have a water table issue even if I never dug around my foundation. It just would of took a bit longer due to my compacted dirt around my foundation.

Rising vs. Falling Water in a Basement

Dalton, I hear and appreciate your frustration with this issue. However, what you describe is not evidence of a rising water table. Rather, water flows from a higher elevations to a lower elevation. When you dug out the foundation, you inadvertently created a "perfect storm" that no doubt worsened this problem. Disturbing very compacted soil by digging it out, even if the goal was to seal a wall was really not necessary. While I'm glad you seem to be at the ends of this process, I'd respectfully suggest you would have been just as successful by properly regrading your foundation and extending downspouts (assuming you have a correctly designed roof gutter system) away from the foundation by whatever means necessitated by your site elevations.

Eating your words

Few people that commented actually know all this is bogus. I can not believe that you are a home inspector for 20 years and can make statements like these. I am not a contractor or home inspector. Just a do it yourself type of guy that took on the project of waterproofing my triplex. I had water in the basement. So the first thing I figured was, like tom was talking about, bad graded land(which there was) and gutters were not draining far enough from house. But before I handled that I excavated around my entire house(5 feet down with a shovel) to repair cracks, apply a water membrane, protection board, and drainage pipe by footer. I did all that and before I was going to put in my drainage pipe it rained pretty steady for 2-3 days. I woke up with a moat around my house. My wife woke me up with, "baby there is water in your hole". That is a ongoing joke with us I knew it was not my gutters or slope because I had plastic all around my house. Like a plastic skirt around my house that was attached to my sill plate to the top of my huge mound of dirt. So it wasn't rain water getting in. I removed my sump pump from the basement and put it outside to pump out my moat. When the sump pump finally removed most of the water there was a steady stream of water(like a river) still trying to fill my hole. This is when I realized that my water table rises after about 2-3 days of heavy rain. After rain it takes about a day or two for the water table to go back to normal. About 12 inches below my footer is the normal water table. This happened a few times because I had to come up with a new game plan. So my point is that Tom is a idiot and I wish I could slap this guy. I don't want to punch him. Just give a a slap of shame for making such idiotic comments about water tables. Let a very dedicated diy'er explain something to you. You must not live in a area that gets rain. Here is how someone builds on a water table. You can build a house in the summer and not know the water table rises during rainy seasons. Your brother probably built my basement with your If two days is a slow rising water table then you are correct. That is not slow to me. MOST leaking basement,if properly done, are very expensive to fix unless you have problems like the gutter or slope. I did all the work my self and still ended up paying a big chunk of change for the materials. I have yet to figure my RISING WATER TABLE out yet. Because if I put drainage pipe next to the footer and drain the pipe to a sump pump. I am going to need a very high output sump pump. And if I drain in to the back yard then the water table will just rise to the point of nothing draining. So my solution was to get a very high output sump pump. Next I am going to make a internal drain system under my slab with drainage pipe that also leads to my sump pump. But I am still worried because I learned that a water table is very hard to pump out at the rate it is filling back in. So I am going to grade the basement floor to my sump pump in case water gets in. I am going to build my sub floor above my basement floor so nothing gets wet. If I have a leak(which eventually I will) it will slope to the sump pump. I have yet to do this because I am making sure I do it right. So if anybody has any advice please inform. Please don't give advice if you agree with Tom.

Your timber flooring is also

Your timber flooring is also at risk if there is water leaks throughout the home. I would never waste time with friends advice, no matter how meaningful or experienced. Ensure you have a complete inspection and act promptly.