Look outside to begin solving basement flooding issues

Q. We have a tri-level house. Over the past three years, the basement has flooded three times - twice to the point where it ruined carpet. It happened again two weeks ago when we got hit with flash floods.

I am in the process of cutting 12 inches off the bottom of the drywall and installing moisture-resistant drywall, replacing the door jambs and base trim with poplar, and I am going to prime that on all four sides so we do not get the wick of the water into the wood.

In the crawl space, we found that there are no tiles around the inside of the crawl space that run into the sump. My plan is to dig around two sides of the foundation on the interior about 18 inches and add a layer of gravel or limestone, lay a drainage tile in the trough, and also add another sump pit at the front of the house.

It is my belief that the water has to be coming from those two sides (the third side is the living area, and the last side has a three-season sunroom running the entire width of its foundation wall), so if I add the drainage tile and another sump pit and pump, I should be protected from the floods. I am also going to extend the two downspouts a good 12 to 15 feet from the foundation.

Let me know your thoughts and if you think I am on the right track, and also what I might use to seal the edge of the water-resistant drywall when I have to cut it and there is an unfinished edge. I am going to leave the drywall about three-quarters of an inch from the concrete slab that is the finished floor (with carpeting).

A. I assume that the crawl space is on the same level as the flooded basement. Otherwise, the crawl space would have to be filled to the level of the basement for the water to enter and damage it.

What was the condition of the crawl space during the basement flooding, which makes you feel the need to install drainage and a sump pump in it?

Most causes of basement leakage are grade deficiencies. Before attempting any corrective measures inside, you should carefully look around the perimeter of the foundation. The grade should gently slope away from the house on all sides, as should all appendages.

Flat or negative grades, plantings against the foundation (especially if mulched), appendages sloping toward the house, roof water not properly disposed of - these are the main culprits, though there are others.

Correct any and all deficiencies and see if that solves the problem. If the leakage is due to an underground spring or a rising water table, both infrequent occurrences, it usually requires interior work.

Where you have had to cut the drywall, is the bottom plate pressure-treated? If not, does it show any signs of damage besides water stains? It should be allowed to dry thoroughly before sealing it back in with drywall.

The fact that you plan on using water-resistant drywall tells me that you expect more water penetration, so why use poplar, which is not very water-resistant? Consider instead using a composite material for jambs and trim.

If you find that you have the need to install drainage in the crawl space, avoid limestone and use egg-sized stones. And while you are at it, consider not limiting the drainage to just two sides; do the entire perimeter and be done with it.

You do not need to dig a trench 18 inches deep; 8 to 10 inches should be enough.

If the grade slopes away from the foundation, you do not need to extend the downspouts as far as you are planning to do. Place a concrete or plastic splash block under their shoe and let the water disperse on the lawn.

As to the raw edge of the drywall, I assume that you mean the bottom edge, as the top edge would be against the existing drywall, and the joint would be taped and get three coats of joint compound. The bottom edge of the drywall would be covered with baseboard trim. Just keep in mind that "moisture-resistant" does not mean waterproof.

I hope this covers all your questions. Good luck with the project.

Q. My concrete driveway has large black areas, which I assumed was dirt, but someone told me was mold. If this is so, how do I treat it and what can I do to prevent it?

A. Since you are unsure of what is causing the black areas, try cleaning them with TSP-PF.

Sprinkle the crystals onto the stained areas, sprinkle hot water on the crystals and brush them with a stiff-bristle brush on a long handle. Rinse with your garden hose.

If this does not completely clean the stains off, use a mixture of one quart bleach and three quarts water and brush the concrete driveway with it. Be aware that these procedures are damaging to vegetation.

Q. First, I really enjoy your very informative column. Can we have your opinion on our Marvin Windows? The inner portion of the sash is beginning to rot. They are only 10 years old and we have no condensation inside in the winter. I feel there is no reason why the wood should be rotting. This was a very expensive window wall.

A. This sounds like an unusual situation. Marvin Windows had a problem some years ago with poor treatment of their wood parts by a subcontractor, but I believe that this was long before 10 years ago.

Contact a local Marvin Windows dealer and have them send a repair tech to see if he or she can figure out what is causing this and offer a solution. Hopefully, Marvin will take care of it at no charge.

Q. I have a deck on the back of my house that needs refinishing. My late husband built it almost 30 years ago and it has held up quite well.

The problem that I need help with is this: How do I remove the gray stain that has been chipping off for the past few years? My family has tried using a belt sander and a power washer, but they really don't help. I want to get the old stain off so I can put on a nice, light-colored stain. Thank you for your help!

A. If the finish your husband applied is really a stain, it must be a solid-color stain, as a penetrating stain would not chip off.

The simplest solution may be to use a paint remover. Savogran makes a variety of paint removers/strippers. Choices include Strypeeze Semi-Paste, a semi-gel that clings well to surfaces without runoff; Liquid Kutzit, which is OK for flat surfaces (both are highly flammable and can only be used outdoors); Heavy Duty SuperStrip, which is nonflammable, if a tougher stripper is needed. If you prefer a biodegradable stripper, Savogran makes Biodegradable Strypeeze.

Some of the removers are water-washable, which makes removal of the loosened paint easier than scraping.

Q. We have a Genie garage door opener, and on sunny days when the sun is focused on our door, we cannot close the door after pulling the car out. The door will start to close and then lift up again. The only way to close it is to go back in the garage and HOLD the button down until it closes. Then we have to go out the front door and be on our way. Is there a device we can use to shadow the sun? Genie was unable to offer a solution.

A. The sun is affecting the door's safety sensors. When you go inside and hold the door button, it tells the sensors: "OK, but I am going to ignore you. Close the door!"

Try this: Clean the two sensors' lenses and check their alignment - it may be off enough to cause a weaker signal. If the problem is not caused by dust, dirt or misalignment, there are some ways to correct it. Make a shade with whatever material is suitable (a soda can with both ends removed, for example) and install it in a way to prevent the sun from reaching the sensor(s) without affecting the beam between the two.

Or move the affected sensor(s) back a few inches into the shade of the garage, but make sure that the alignment is not affected negatively.

Better yet, have an experienced garage door specialist do the job for you. Call several garage door specialists, discuss your problem, and choose one who fully understands it.

You haven't told me where you live; if you are in Vermont, I would direct you to Limoges & Sons Garage Doors in Williston, who have handled a number of these problems that others could not fix.

Interesting follow-up from a reader: "We had some contact a couple of years back when we were doing some projects and your advice was always solid.

"At about this time last year we had a small detached garage built and I found myself referring to your columns for various aspects of the construction.

"I am writing today concerning the question from a reader about sealing their granite countertops. Back in 2006, we swapped out the Formica countertop for granite. We went with one marketed under the name 'Ubatuba,' which is primarily black with gold and green flecks.

"As I am sure you are aware, many stones marketed as granite are not, geologically speaking, true granites. This Ubatuba and several others are classified as charnockites, which are exceptionally dense. As such, aside from some sealing that may have been done at the factory, there can be no additional sealing as the stone will not absorb the sealer.

"Your reader may have a similar situation. We continue to enjoy your columns of which I have saved several for reference! Thanks again."

• Henri de Marne was a remodeling contractor in Washington, D.C., for many years, and is now a consultant. Email him at henridemarne@gmavt.net.

© 2016, United Feature Syndicate Inc.