If you’re thinking about staying put, but "expanding", start by looking at your basement. Assuming that it’s dry, and that heating and cooling ducts are in place, you may be able to quickly and economically convert your basement into valuable living space simply by painting it.
In all probability, your basement has masonry walls of one type or another, most likely cinder block, cement block, or poured concrete. If so, you’ll want to go about painting them the right way.
Start by inspecting the condition of the walls, and taking steps to prepare them for painting. Scrape off any loose or peeling paint. Then use a wire brush or power brush to remove all dirt, unbound sand, efflorescence, chalk, and remaining loose paint fragments.
Any material that is loose or crumbling should be cleaned out and patched with cement or mortar to create a smooth finish to the wall. Be sure to allow the patch to dry thoroughly before applying any type of coating.
If you see cracks in the masonry or seams between adjoining surfaces, seal them with a quality siliconized acrylic caulk. Unlike similar-sounding silicone caulk, siliconized acrylic sealants are paintable, so they’ll help produce a more attractive finished appearance for your newfound space.
Should you spot areas that have mildew (show me a basement without it!), apply a solution of one part household bleach to three parts water, let it sit on the surface for 20 minutes, then scrub off the mildew.
After completing these steps, thoroughly rinse the surface with clean water to eliminate any residual dust or particles. After the surface dries, it’s on to the coatings!
Tip: Before applying any paint or primer to your masonry, you should lightly dampen the surface; this will aid in proper film formation. Also, if at all possible, keep the area well-ventilated when applying any coating.
If the masonry has never been painted, it will likely be quite porous. To make the surface less absorbent, apply a high quality latex masonry primer or sealer. This will help you get a smoother, more uniform, finished paint job. If you are working with a VERY rough surface, such as rough cinder block, apply latex block filler instead of the primer.
After the primer or block filler is completely dry, it’s time to paint. Since most basements can be little dark, your "add on" will be most welcoming if it’s painted in a light, bright color. Off-whites and other faint tints seem to work best in basements, but when it comes to color, there’s no right or wrong choice.
Once again, dampen the surface lightly. Then use a long-nap roller to apply a very thick coat of top quality 100% acrylic latex paint; or, if you’re concerned about moisture seeping through the walls, you could apply two coats of a specialized top quality vapor barrier paint. Your work is now done.
Having given new life to your old basement, you can use the freshened space in all sorts of ways: as a playroom for the kids, a game room for adults, or a cave for your man. No matter what you decide, your home will be roomier and more functional. That’s the magic of paint!