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Q.I recently requested a quote for 1x4 T&G fir for a covered porch. The lumber supplier added two new species, meranti and Brazilian redwood, to the quote list. How do those woods stack up against Douglas fir, which has been used traditionally for porch floors in my area? I plan to paint all sides of the flooring.

A.Contributing editor Paul Fisette responds: This is a real apples-to-oranges comparison. The short answer is that all of these choices can work for you, but there are distinct differences worth considering.

Meranti (shorea spp.) is commonly sold as Philippine mahogany. But your expectations for meranti should not be confused with the superior properties associated with real mahogany. Merchants separate 125 species of shorea into four groups of meranti. Each has different properties. As a result, when you order meranti, you really don't know what you're getting. It's separated according to color and weight: dark red, light red, white, and yellow. The grain is often interlocked. White meranti dulls cutters because it has a high silica content. The dark red and yellow varieties tend to warp. Dark red is moderately resistant to rot. The light red, white, and yellow versions are not durable in exposed conditions. I would only consider the dark red varieties for exposed locations.

The other new option, Brazilian redwood (Massaranduba), is an interesting choice. It is widely distributed throughout the West Indies, Central America, and northern South America. The wood is hard, strong, and heavy — generally about twice as strong and four times as hard as Douglas fir or meranti. The specific gravity is about 0.85, making it roughly twice as dense as your other options. You will have to predrill to fasten these boards. However, this wood is surprisingly easy to work despite its high density and is resistant to decay and termites. Brazilian redwood is also resistant to water absorption, which helps improve stability. But be careful: The natural oils found in this wood make it tricky to glue and paint. You might want to forget painting and consider treating the boards with a water sealer or penetrating oil to avoid the potential finishing problems and enjoy the natural figure of the wood. If you decide to paint, be sure to experiment with some test boards first.