Must a microwave be installed in a cabinet?

Q. I have a very old microwave oven that I want to replace. When the installer from the store I purchased the new microwave oven arrived at my house to install it, he said he couldn't install it because there was no cabinet above where it was to go. He said there was nothing to attach it to. But my present oven is on the wall above my stove (exactly where I want the new oven) and it is not attached to any cabinet. It looks like it is in a case attached to the wall and that the oven slides inside the case.

Several stores have checked for me and can't locate a similar case, even though the old microwave is a GE Spacesaver which is still made. Do you have any ideas how I can have a new microwave installed without buying a new kitchen cabinet (which I don't want or need), just so I can get my new microwave?

A. Your appliance dealer is correct to the extent that he is following the manufacturer's specifications.

However, I have checked with my favorite appliance dealer and, even though he backed up your guy, he said that you can have a carpenter or handy person install your new oven on the wall only, but at your own risk. An experienced carpenter can figure out how to do it safely.

The safest alternative is to get a wall cabinet installed, but I understand your unwillingness to do that.

Q. I would like to insulate my concrete foundation wall with 1-inch rigid insulation and drywall. What is the best way to do so directly on the concrete without the use of furring strips, as the space is limited?

A. Keep in mind that insulating any type of foundation from top to bottom successfully requires one to be sure that the grade around the foundation is sloping away gently in order to keep water from percolating deeply and causing potential pressure on the foundation in case of deep frost.

I assume you know your plan, although sound, will make no allowance for any mechanical installation, such as electric wall outlets.

To successfully install the two-layer system you are planning to use, make sure the concrete walls are clean; apply daubs of polyurethane caulking compound to the walls and push the rigid insulation onto the adhesive. Then ensure the solidity of the installation with the proper size and type Tapcon masonry screws.

Apply the drywall in the similar manner, again using the right size and type Tapcon screws. Be sure to study carefully the installation of Tapcon screws for concrete, as it is critical to success. Tapcon screws come with a hex head or a flat head; you'll want the latter.

Use a battery-powered nut driver (do not use an impact driver) to drive the screws, but stop short of the surface of the material. Finish with a hand-held screw driver to avoid over driving the screws.

Q. We used Cabot semitransparent stain on our cottage on a lake. We used cedar and primed both sides before installation. The stain just does not seem to penetrate. We did this in 1996 and have restained four times. We also have a lot of mildew and have used a mildew preventer in the stain. I washed the siding with a bleach solution. Any suggestions?

A. You did not mention what type of cedar you used: red or white. If you used red cedar, it generally comes with a rough side and a smooth one. If you chose the smooth side as the exterior face, it may have had what is called "mill glaze," which comes from the milling process.

Mill glazed surfaces need to be either sanded or exposed to several water episodes, such as rain or hosing, to raise the grain slightly.

This is likely to be your problem, in which case, you will need to remove all coating, sand the surface and apply the proper type of stain. Obviously, the Cabot stain you used, even with a mildew retarder, didn't do a good job. Consider switching to Amteco TWP, which has a very good track record of resisting mildew. Check out Amteco's website, www.amteco.com, where you can choose the best hue and type of stain for your purpose.

Q. I enjoy your column in the Daily Herald and have learned a lot from it. Now maybe you can help me.

Whenever it rains we have a leak from our kitchen light over the kitchen table. The window in the kitchen faces south but we think the leak is coming from the dormer window above the kitchen window. Somehow, as we have been told, water is coming in either through the window or the siding and finding its way down the conduit to the electrical box that holds the kitchen light. We had thought of replacing the dormer window but the window supplier says "I can guarantee you that it is not the window" but some other source of entry. We are at a loss as to what to test to find the leak. Our last resort would be to replace the window against his advice. Some ideas we had were to remove the drywall under the dormer window and look for water evidence; spray a hose on that side of the house and watch for the light to leak (but that wouldn't give us the source); replace the siding but we are told that it could not be the source of a leak. Can you help us with some other ideas before we bite the bullet and just replace the window. Anything you can suggest would help.

A. If this has been a problem from day one, my guess is that the housewrap was improperly cut at the window openings and that the top flap was wrapped around the window's top plate. Any window flashing, if one was used, was applied on top of the housewrap instead of underneath it. I have seen this in so many cases of mysterious leaks.

It is most likely that the leakage is at the kitchen window. Consider having an experienced contractor check this out.

Help from a reader: "In response to the writer looking to clean soap scum off shower doors: Nothing works as well as dryer sheets. I use them while in the shower because they need a thorough rinsing. Works amazingly well!"

And another helpful suggestion: "Someone wrote about cleaning newspaper ink off her kitchen counters. I have found Mr. Clean's Magic Eraser works great at getting stains off our counters. I've used it on newspaper ink, rust rings, food coloring and red wine stains. I hope this is of some help. My husband and I really enjoy your column. "

• Henri de Marne, a former remodeling contractor turned columnist and consultant, is the author of "About the House with Henri de Marne" (Upper Access Publishing). He continues to take questions from readers for this column and his website, www.henridemarne.com. Email questions to aboutthehouse@gmavt.net.