Basements vary a lot. Some are a new and clean – a dream to finish, with lots of headroom, bone-dry conditions year-round, and foundation walls that look like the day they were made. Other unfinished basements aren’t nearly so nice. They look and feel like a medieval torture chamber. Dark, damp and distressing, the physical and financial challenges of finishing a space like this can be considerable. In fact, it’s sometimes impossible to finish some basements so they don’t contaminate the rest of your house with mold spores and the smell of mildew. Most basements can be finished successfully, but not all of them. How do you know if your basement is finish-worthy? Think about the basement assessment questions coming up next, then answer them honestly. Just remember, cheating has consequences. Answer truthfully and accurately and you’ll be the big winner. Don’t let hope and enthusiasm cloud your judgement. Ideally, the assessment exercises you’ll find coming up are best done on an unfinished basement with junk removed. Walls and floors should be open and visible. If you’re basement is currently finished and you’re planning to gut and refinish it, the work of observation is still possible but more challenging.

Basement Assessment Question#1: Is It Really Dry Enough?

A reliably dry basement is a completely non-negotiable starting point for any plan to finish the space. You may have terrific ideas for a great space down there, but the entire basement needs to be 100% completely dry, 100% of the time before finishing should ever happen. If your basement “leaks a little”, or “leaked the last time we had a really hard rain”, or “sometimes gets a bit damp when the snow melts quickly”, forget about finishing until you get the place reliably dry. And I mean bet-your-life dry. It’s that simple. It always surprises me how many people let an excess of hope and enthusiasm get the better of them in this regard. They go ahead and finish a basement that they know gets “a little wet” or fail to observe a seemingly dry basement long enough to know that it really isn’t all that dry. Heartache always ensues, along with harmful indoor air quality and a deflated pocket book. 

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TRUE STORY: FINISHING A WET BASEMENT

For about ten years I had regular Sunday afternoon visits from a couple of well-dressed religious men who came with colourful pamphlets. A guy named Bill was always one of the team. Living in a small rural community as I do, my visitors knew that I was involved in construction and renovation, just as I knew a lot about them. This sometimes gave the conversations an unusual turn. We might start with questions about home improvement projects or power tools before my guests abruptly made the leap to things above. One day the topic of basements came up . . . 

“What can I do to stop the waferboard in my basement from swelling and going moldy”, Bill wondered. 

“How long has this been happening?”, I asked. 

“Ever since I finished the basement 6 years ago. I knew we usually get a little water in the basement in the spring, but this year’s worse than usual. Is there something I can kill the mold with?”

Bill was genuinely surprised when I explained that there are no easy solutions. In fact, there are no solutions at all to finished basements that are wet and moldy. Some problems are easy to fix, but a chronically leaky finished basement filled with moldy wood isn’t one of them. He never should have finished his basement until he got the leaks fixed and at least one year of dry performance had happened. Bill bought and installed tens of thousands of dollars of materials to build what amounts to an active compost pile in his house. I wish he had asked me before he built. He wishes he had, too. Helping you avoid trouble like this is one main reason for this course

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How to Check for Basement Moisture 

So, how do you know your basement is REALLY dry? It takes time to do a proper job because water leaks or damp conditions don’t usually show up all the time. It also takes attention to detail a little detective work to properly assess the waterproof status of a basement. If your basement is already finished, your nose may tell you if moisture of some kind is a problem. If the basement smells musty at any time of the year, you’ve got a moisture issue hidden somewhere, guaranteed. This might be liquid water leaks (visible or hidden), but it could also be internal condensation developing in exterior walls and floors. If your basement is currently unfinished, before you get your basement-finishing hopes up, complete the following two-step procedure. You don’t want to end up like Bill . . . 

Basement Moisture Check#1: Begin by watching your basement carefully for at least a year. 

Longer is better. This sounds crazy to some people, but even a year isn’t always long enough to spot serious moisture problems. Why bother? Mostly because water can only leak into a basement if enough of it exists outside your house. You might get lucky and your basement really turns out to be dry even without you proving it to be so. That’s great, but you can’t count on it. Enthusiasm is no reason to gamble tens of thousands of dollars of materials and labor – plus your family’s health – finishing a basement that shouldn’t be finished in its current state at all. You need to see if your basement really has what it takes to stay dry when the going gets wet outdoors. Regularly inspect your basement with a flashlight looking for damp patches or outright liquid water. A good LED headlamp is even better than a flashlight. You’ve got to be a Sherlock Holmes about the issue of basement wetness to avoid coming to grief. 

Click below for a video tour of my favourite LED headlamps. Simple as it sounds, I consider LED lights like these to be a small but highly useful basement finishing tool. A headlamp lets you do a much better job identifying moisture and mold issues, and it’s also handy during construction when you need to see things in less-than-ideal light.

VIDEO: LED HEADLAMP TOUR

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TECH TIP: A MOISTURE METER CAN HELP

If you have an old basement that’s currently finished, analyzing the wood is worth doing before tearing it out. This is where a moisture meter can help. These small, economical, hand-held electronic devices are used by woodworkers to measure the % moisture content in wood. Stick the prongs of the moisture meter into the wood, hit the button and the meter will tell you how wet the wood is. If there’s old wood framing in your basement, it’s definitely worth checking with a moisture meter. Anything more than 12% to 14% moisture content is too high (especially in wood near the floor) and shows that you have a moisture issue that needs addressing. This might not currently be obvious, but wet wood never lies.

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Basement Moisture Check#2: Monitor water vapour infiltration. 

While you’re monitoring your basement for signs of liquid water leaks, you need to keep your eye on something else. Damaging levels of water can enter your basement in the form of invisible water vapour as well as liquid water. Cut three or four 24” x 24” pieces of clear plastic (the kind used as vapor barrier works great), then fasten these pieces to walls and floor with duct tape. Brush the masonry surface clean to remove dust or loose particles before the tape goes down, then check to make sure the tape hasn’t come loose. Look at the plastic every few days for a couple of weeks. You’re looking for signs of condensation or water droplets on the INSIDE surface of the plastic. If moisture is coming in through the masonry as vapour (and it’s entirely possible), it’ll show up inside this plastic. 

I often hear from homeowners by email who build typical wood stud frame walls on the inside of exterior basement foundation walls as part of their finishing campaign “the way it’s always been done”. They fill the cavities with insulation batts, then cover the frame with vapour barrier plastic before eventually applying some kind of interior wall finish. Drywall or wood panelling is popular. 

If the homeowner doesn’t happen to install drywall right away, it’s not unusual for condensation to develop and be visible on the inside face of the clear vapour barrier plastic. This is especially common in summer. In a sense, they’ve created a moisture vapour infiltration test the hard way. “What can I do to fix this problem?”, they ask me, concerned.

“Turn back the hands of time and prepare your basement walls correctly” is all I can say at that stage.

I know it sounds harsh, but it’s true. Better to put some small pieces of plastic on your walls to monitor them right at the beginning of the process rather than discover the need for moisture control after your walls are up. 

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QUICK DEFINITION: STUDS & PLATES

Studs: Vertical pieces of wood or metal that form a wall frame. Many houses have stud frame walls on the outside, and studs are often used in basement finishing, too. As you'll see, I don't recommend stud walls for exterior basement walls. Commonly used as they are, they're not ideal.

Plates: Horizontal pieces of wood or metal that connect wall studs together top and bottom. In the basement design you’ll learn about here, there’s one “top plate” that connects the top ends of partition wall studs, and another two plates that connect the bottom. The lower bottom of these bottom plates is a non-organic rot-proof material. The second one up can be wood. More on this later.

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More on Moisture Testing

The painting and floor coating industries have developed sophisticated tests to determine the moisture levels of concrete floors and you’d be wise to make use of these tests yourself. One long-standing moisture test for concrete involves something called the ASTM 1869 standard. It was developed in the 1950s and uses a container of dry calcium chloride underneath a plastic cover sealed over the concrete floor. That's what you see above. Prep the concrete so it’s clean and bare, open the pre-weighed container of moisture-hungry calcium chloride powder, write the date and time on the container, then use tape to seal the plastic cover to the concrete with the calcium chloride inside. The more moisture this white powder absorbs in a given period of time, the more moisture’s in the concrete. At least that’s the theory. Weigh the calcium chloride after 60 to 72 hours with some kind of sensitive scale such as a postal scale (great digital ones are available cheaply on Amazon for less than $35), then plug the weight figure into the formula that came with the kit to determine the moisture content of the concrete in pounds of moisture emitted per 1000 square feet. Most coating manufacturers allow no more than a 3 pound moisture rating on concrete for warranties to apply. Some coating and flooring manufacturers even require moisture testing results be recorded for warranty coverage to kick in. This is fine except for one problem. The calcium chloride test only measures moisture levels in the very top part of the slab. You can get a superficial reading on a fairly new concrete floor that’s dry enough,  but still have problems later because moisture migrated up from deeper in the slab over time, causing issues. Allowing one year to observe your basement before finishing is especially useful when you’re dealing with a new concrete floor that needs time for interior moisture to escape.  

So what can you do if your basement proves to be less than perfectly dry? Finishing may still be possible, but only after steps have been taken to ensure year-round dryness. And to be honest, most of the big things that need to happen to make a wet basement dry aren’t things ordinary homeowners can do. Sure, you can get downspouts, eavestrough and properly sloped grading in place, and this might solve a wet basement problem. If it doesn’t, then your basement needs some heavy duty help. More on this in week#2.

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TRUE STORY: TOXIC BASEMENT AIR

For about 8 years, my kids and I grew pick-your-own raspberries for sale, and sometimes we’d pick berries for elderly people who couldn’t pick their own. One July afternoon I knocked on the side door of a house in town, the home of a woman who I knew had serious breathing issues. I was there to deliver 8 quarts of raspberries we’d picked for her. Over the years I’d seen this woman around town with a rolling oxygen tank and clear plastic tubes fastened under her nose, and I saw the same thing when she came to the door a long time after my knock. As she opened, I could immediately see she was pleased with the berries but I also gained an immediate insight into her health condition. The door was located on a landing, a few steps down from the main floor of the house, and more than a few steps up from the basement. Some of the strongest odours of mold and mildew I’ve ever smelled came rolling out of the door when she opened it. I knew she had a classic and very serious case of moldy basement syndrome. This is the kind of thing that affects the healthfulness of an entire house. Was this the cause of her chronic breathing issues? I don’t know for sure, but it certainly could have been. I’ve seen people completely cured from lifelong asthma and ineffective drug treatments after I helped them improve the quality of indoor air in their homes. Bottom line: Indoor air quality matters much more than most people realize, and basements have a lot to do with that air quality.

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Have you found white, fluffy growths on the inside of your basement walls? This may look like mold, but it’s probably what they call effluoresence. No need to panic! Listen to the audio lesson coming up to see what efflorescence is and why it’s different than mold (and harmless, though it does indicate something significant).

AUDIO: IDENTIFYING AND UNDERSTANDING EFFLORESCENCE

Basement Assessment Question#2: Is It Structurally Sound?

Your job now is to honestly determine if your basement is worth finishing, apart from any issues to do with moisture. I’ll explain more about the different types of basement construction next week, but in the mean time just take a general look at what you’ve got. Basement height is a good place to start. Insufficient basement height is more likely to be an issue with older homes than new ones, and the trouble is obvious. A short basement isn’t worth finishing because it doesn’t afford enough headroom. So how high is enough for finishing a basement? Many jurisdictions require at least an 84” ceiling height (not including occasional areas of lower height for heating ducts) before they’ll issue a building permit for a basement renovation. Can a home be raised to create more basement headroom? Yes. The basement floor can also be lowered by removing the existing floor, digging out some soil, then re-establishing a new concrete floor, new support posts and by shoring up the area around the footings. The thing is, all this is quite expensive an troublesome.  In extreme cases it can cost as much to raise a house as it would to finish the basement space lavishly. So a low basement ceiling height could be a deal breaker as far as finishing plans go unless you’re committed to making more headroom first. As you think about all this, remember that you’l lose a little height for flooring and ceilings.

Assuming the height of your basement is suitable, examine the condition of foundation walls and the floor. You’re looking for significant deterioration in the form of cracks and crumbling masonry. Both of these conditions could be insignificant or they might matter a lot. That’s what the questions up next will help you determine. Choose the first set of questions if your basement is unfinished, and the second set if it’s currently finished.

Questions for assessing unfinished basements . . . 

Are there visible cracks in the walls and floor?

It’s not unusual for masonry structures to develop narrow, short, hairline cracks here and there. These don’t matter so you can ignore them. But are there obvious cracks in the walls or floor that have some visible width to them? Are they longer than a foot? 

If NO, proceed to Basement Assessment Question#3. You’ve got a crack-free basement and that’s a good thing.

If YES, your job is to figure out if the cracks matter and what, if anything, you can do about them. Continue by answering the following questions.

Monitor cracks over time. A stable crack is probably a harmless crack.

Record the width of all cracks at designated places every two months.  Also, draw a line across the crack so you can see if one side is shifting relative to the other. The time required to prove that your basement is dry is also a good time to monitor cracks. Vertical cracks in a poured concrete basement wall usually indicate harmless shrinking of the foundation wall. Horizontal cracks are potentially more serious because they can indicate an inward failure and progressive bowing of the foundation because of soil pressure. In both cases, monitor crack widths. In the case of horizontal cracks, also monitor how flat the wall is and remains. The video up next shows how and why this is important. 

VIDEO: ASSESSING BASEMENT CRACKS

If You Found Stable Wall Cracks . . . 

If stable cracks are wider than the thickness of cereal box cardboard, then consider filling them with injected epoxy. Better yet, use a system of injection to fill the crack plus carbon fiber fabric bonded to the surface for added strength and resistance to future cracking. More on this later in this lesson. You can get DIY kits for this or call an epoxy injection specialist. Some people get overly concerned about filling stable cracks, assuming that unfilled cracks make the basement more likely to leak. This isn’t as true as you’d think. Basements are not boats. Masonry is not very waterproof on it’s own, and when water is present outside a foundation wall, it’s probably going to get in, with or without cracks. Go ahead and fill small stable cracks if you like, but it’s not a make or break issue as far as moisture-proofing goes.

If You Find Stable Floor Cracks . . . 

You can fix these with epoxy and carbon fiber the same way as with stable wall cracks. Floors are less likely than walls to have cracks large enough to fill because floors aren’t under the same stress as walls, but you might as well fill if you want.  

If You Find Unstable Wall & Floor Cracks or Sunken Floor Areas . . . 

I’m afraid this is bad news, but better to know now rather than after you’ve spend a bundle of money finishing a basement that may have serious structural problems. Finishing a basement with active, unstable cracks is almost as unwise as finishing a basement that gets wet periodically. If you’ve got unstable cracks or sunken floor areas, call in three or four structural basement repair specialists and see what they say. You can assess the trustworthiness of their advice by talking to at least three previous clients from each contractor.  Don’t skip this step unless you don’t mine the horrible feeling of paying thousands of dollars to someone who doesn’t know or care what they’re doing. This sad situation is much more common than it should be.

Is there visible rot or signs of insect attack in wooden framing members?

Most basements have some kind of wooden framing members supporting the floor above, even if the basement walls and floor are made of masonry. In the case of a wood frame house, wooden framing members also include the bottom ends of the walls that sit on top of a masonry foundation. Either way, now’s the time to look closely at all these wooden elements for trouble while the basement is still open and visible. Once again, an LED headlamp is ideal for this examination because it leaves both hands free while directing lots of light on the subject. The thing is, bad wood doesn’t always look bad from the surface. Considerable rot and insect attack can be hidden under a thin layer of seemingly sound wood. Always poke around with a large screwdriver or pry bar to make sure that good-looking wood really is good and solid. You’ll need to fix any deficiencies now because the wood framing will be covered later by your finished basement ceiling. Pay special attention where wood framing meets outside walls, and any place where drains have penetrated the floor above. Slow rainwater leaks around the perimeter of the basement or chronically leaking drains are the most likely sources of moisture that leads to rot. The ends of main wooden beams are particularly susceptible to rot where they meet outside walls. Did you find any rot, holes or fine sawdust that might indicated insect attack?

If NO, then proceed to Basement Assessment Question#3.

If YES, then learn all you can about the deterioration by examining it more. How extensive is the area of deterioration? Is there rot only? Insect attack only? Both? Your job now is to figure out what’s going on, then get your unique issue fixed before proceeding. Send me photos and I'll get back to you.

Deciding what to do about wood frame deterioration is a case-by-case issue and a successful repair often demands advanced carpentry skills of a creative sort. There’s the issue of fixing the cause of the deterioration in the first place (leaky siding, insect entry points, leaking drain, etc), then there’s still the job of replacing the punky wood itself. Fortunately, deteriorating wood framing above basements is relatively rare. And while it’s true that the majority of homeowners need professional help to deal with this kind of issue, you can’t simply ask any carpenter you find for their opinion and expect to get a useful answer about what to do. Not all carpenters are created equal. When calling in help for a unique job like this, you need to understand how to find the right kind of carpenter. Click below for audio tips on the person you’re looking for and what it takes to complete wood frame repairs that require creativity and patience. 

AUDIO: HOW TO FIND A CREATIVE CARPENTER

Questions for assessing finished basements . . . 

Assessing a previously finished basement offers less certainty than examining an unfinished one because the wall board, floor covering and ceiling prevents you from seeing what’s going on. That said, you can infer a lot from what you do see and smell in a finished basement. If there’s any sign of previous water presence on the bottom of walls and floors, then you know something bad is going on behind the scenes. You really shouldn’t ignore anything like this. Also, your nose will tell you a lot. Any smell of mold and mustiness is a strong indicator of a moisture problem that’s affecting indoor air quality throughout the house. If there’s carpet on the floor, get down and smell closely. Carpet has been installed improperly in basements for decades, so it’s a common source of trouble.  Click to hear a true story about a basement, carpet, humidity and mustiness.

AUDIO: BASEMENT CARPET AND SUMMERTIME MUSTINESS

Click below to watch a video animation that shows how carpets installed on concrete promote mold and mustiness. As you’ll see, a subfloor is the solution.

VIDEO: THE CAUSE OF BASEMENT CARPET MOLDINESS.mp4

Basement Assessment Question#3: Is your electrical system up to the job? 

Every finished basement requires at least basic electrical outlets and lights. If your plans include a workshop space, you’ll need even more power. Same goes for a kitchen. Find the electrical panel that services your home (almost always in the basement) and see if it has the physical space to handle the extra circuit breakers a finished basement will require. This is simply a visual thing. You could easily need 6 or 8 new circuit spaces on your electrical panel – perhaps more. Does your existing electrical panel have modern circuit breakers or old-fashioned fuses? Are there at least half a dozen empty spaces to accommodate additional basement circuits? 

If YES, then you’re ready to move on.

If NO, then call an electrician. It may be possible to add a second panel to an electrical system that’s otherwise modern but doesn’t have physical room for additional circuit breakers. That’s a relatively easy job for a pro. On the other hand, if you have old wiring or you’ve maxed out on the amperage that your current service can deliver, then you might need an entirely new electrical panel and feed cables. That’s almost always a job for a pro and it won’t be cheap. Thankfully, the need to upgrade the electrical capacity of an electrical system to make it possible to finish a basement is rare.

Click on the video coming up next for a tutorial on how electrical panels work, how they’re sized and to understand the circumstances where you might need a new panel.

VIDEO: UNDERSTANDING YOUR HOUSEHOLD ELECTRICAL PANEL

Is your basement finished now, but you’d like to refinish it? In one sense this is a simpler situation than assessing an unfinished basement because there’s so much less to see – at least at first, until you strip back to bare exterior walls.  In another sense stripping back an existing finished basement might turn into a big can of worms because you could discover structural issues that you didn’t expect. What should you do? If you’re on the fence about whether or not to take everything back to bare walls, one way to help decide is by assessing indoor air quality. If your existing finished basement smells musty at any time of year, then do some indoor air quality testing.  How musty is musty enough to warrant stripping back to a fresh start? Airborne mold test kits are available for homeowner use or you can call in an airborne mold testing professional. If you test with a kit on your own, choose one that actually circulates air with a fan and collects airborne samples. Run a household fan in the basement for a while to stir up the air, then set up your sampling device 3 or 4 feet off the ground. If testing reveals dangerous levels of airborne mold, then stripping back to bare exterior walls while also taking health precautions by wearing a HEPA rated respirator is a great idea. You’d want to do this even if you don’t end up refinishing the space completely. Alternatively, if the air in your basement checks out fine mold-wise, then stripping and starting from scratch is more of an aesthetic choice. Chances are that older, finished exterior basement walls have rather low insulating properties, so that's a consideration, too.