CHRONIC MOISTURE problems can lead to mildew and mold, which make the house smell strange at least, and can cause health problems at worst.

The good news is that standard Alberta building practice prevents most basement leakage, and householders themselves can solve most of the wet-basement problems that do occur.

The not-quite-so-good news for home owners is that some effective moisture remedies require them to re-think their approach to landscaping. Anything that encourages water to accumulate in the soil next to the basement wall is a potential problem – you may well get away with it, but why tempt fate?

“Eighty per cent of water challenges in basements are because of poor drainage,” says Michael Nyikes, director of technical affairs for the Calgary Regional Home Builders Association.

“If you can make sure your downspouts are four or five feet away from your foundation wall, then there’s not so much saturation of the soil against the foundation wall. That will minimize water permeating into your basement,” Nyikes says.

Those flip-up downspouts that are so handy when you mow the lawn can be a problem if a heavy rain comes along. “The trouble is that people forget to put the spouts down again, and then they’ve got water going into the corner of their foundation,” says Clarence Burke, a leading Calgary renovator who owns Burke Builders.

It’s the easiest wet-basement solution of all: make sure your downspouts are emptying well away from the foundation. Otherwise, they’ll deliver all the rain that falls on your roof into a few very small spaces right next to your basement wall.

“A lot of people encourage their own problems,” Nyikes says. “They will put planters or garden areas against their foundation, instead of perhaps doing sod, or rock or concrete.

“When you have bare dirt in a garden against your foundation wall, you’re always watering it, because you want your plants to grow, and the bare soil is capturing rain because it’s more absorbent and water doesn’t have a chance to run off,” he says.

The most important precaution a householder can take is to make sure that the ground slopes downward away from the foundation wall. It doesn’t have to be a conspicuous slope – two or three inches of drop in a run of eight feet will steer water away from the house.

Builders routinely grade the yards of new homes to provide this slope. Unfortunately, there’s a problem that appears after the owners move in.

Basement excavations are deliberately made oversized so that construction crews can work on the outside of the foundation wall. When the work’s done, the gap between the foundation and the surrounding soil is filled in again.

But this backfill isn’t as tightly packed as the soil that’s been undisturbed for thousands of years. For a year or two after construction, the backfill settles, creating a kind of saucer around the foundation. This sinkage occurs with every new house, Nyikes says.

“One thing I see very, very commonly, which causes great challenges for builders and landscapers, is that when a consumer moves into their house the first thing they want to do is put their grass down.

“It’s the worst thing they could possibly do, because  within a year and a half they’ll find that the grade has settled all the way around their foundation wall, and they’ve got negative slopage,” Nyikes says.

“They don’t want to rip up all that nice grass that’s now established. So then they have water problems, and they’ll call the builder and say the builder obviously dd something wrong. That’s not necessarily the case.”

 He has some advice that may not be welcome to new home owners: “Most builders will advocate that the consumer does not do their landscaping for at least a year after they have taken possession of the home, otherwise they’ll have drainage problems.”

Backfill will settle, Burke agrees. “Before landscaping, it’s a good idea to do some compaction, or you’ll have to do it twice. A lot of people don’t landscape right away, just to make sure it’s compacted well so they don’t have issues later,” he says.

Calgary basements endured a severe test in last year’s record June rains. Some filled with water up to ground level, but the majority came through dry.

Modern construction standards deal with water two ways: by draining it away from the bottom of the foundation, and by blocking its passage with a coating on the outside of the foundation wall.

New homes have foundation drains right beside the footing, which is the wide concrete slab that bears the weight of the house.

The basement wall rises from the footing, and the basement floor slab is poured as a separate slab of concrete inside the wall. Saturated soil next to the house can force water through the gaps between these pieces of concrete.

The foundation drain, called weeping tile, relieves this pressure. It’s a large, perforated plastic pipe that collects water and delivers it to a storm sewer connection or to a sump below the basement floor.

The sump may empty itself again through the weeping tile when a rainstorm passes, or it may have to be drained by an automatic pump.

The concrete of the basement wall will let some water seep through, so builders are required to spray a coating of tar onto the outside.

For more money, builders can instead use dimple board – sheet plastic, with bumps on one side, that’s fastened to the outside of the basement wall.

“It works really, really well,” Nyikes says. The bumps create an air space next to the wall, for better drying, and the solid sheet keeps moist soil from touching the concrete.

Incidentally, Nyikes says new home owners needn’t worry about hairline cracks in the walls or floor of their basement. “Cracking will always happen – that’s just the nature of the material.”

The building industry has a rule of thumb – or finger – that says you should seal a crack if you can put your pinky in it. “It’s a matter of having epoxy caulked into the cracked area. It looks bad but it will seal off the crack,” Nyikes says.   NL