Window Sill Detail /Exterior Lumber

[Dan Lautner]

I'm looking for a good hardwood to use for the window sills shown below. I want to finish it clear. I have over 60 lineal feet of sill to install. Teak seems to be the best choice but very expensive. I was thinking about genuine mahogany or maybe Ipe. I need 7/4 stock, 12" wide and 13' lengths. Any advice on what would be a good exterior wood I could get in these sizes? Thanks for any input/ advice.

Dan

[David Wilson]

Dan
Don't know if it available in your area but White Oak would be a good alternative.

[Jim Becker]

I know that Hearne Hardwoods where I buy such stuff, carries mahogany in long lengths...the 8/4 stock I bought for my last mahogany project actually was 13' lengths x 11-12" wide, although at the time I didn't have the trailer and had them cut it down for transport.

[David DeCristoforo]

Mahogany ain't cheap right now but it's a great wood for making windows (or sills). Don't forget, they build boats out of this stuff...

[Ben Grunow]

Red cedar (same as your siding) might be a good choice but it is very soft if the sills are near a deck or something. It is usually readily available in 2x12 too.

I would go with mahogany or ipe other wise. Glue up if you have to (epoxy or resorcinol).

[Floyd Harper]

spanish cedar.
Very durable for the conditions described. It is also reasonably priced.
They have 8/4 on sale near me for $1.50 bd foot.

[Rich Engelhardt]

Hello Dan,

I'm looking for a good hardwood to use for the window sills shown below. I want to finish it clear.

Are you 100% positive you want to do that?- finish them clear?
Clear coats - outside - where they are exposed to the full brunt of UV rays break down quickly.
It's possible that you may be facing the job of sanding them down and recoating on a yearly - if not more often - basis.

[Richard Wolf]

Another vote for Spanish Cedar. It seems to be the new outdoor wood to be using.

Richard

[Steve Schoene]

Let me reinforce what Rich said. There is NO clear finish that would not have to be sanded and a refresher coat applied regularly. In Southern California, that would be AT LEAST annually, and on southern exposure it could even require twice a year recoating. You might be able to stretch the interval slightly with an initial epoxy sealing, followed by a number of coats of a two-part clear marine finish at about $80 for a quart size "kit", including the necessary thinner.

After 5-6 years, while you would still be waiting before the first paint recoat was needed, you would likely have to strip to bare wood, and reapply the clear finish. If you got an extra few years with the two-part system, you would pay for it by extremely difficult stripping. There would be parts failing and turning grey because the wood had begun to deteriorate, but other parts might be tenaciously hanging on.

The merit of particular woods, teak, mahogany, etc. is that they weather well without coating, turning a rich shade of grey depending on the variety. But they all breakdown under clear finishes, loosening even the best of finishes. UV absorbers in the finishes get "used up" and don't protect forever.

So, unless you are willing to devote a continuing chunk of time to maintaining these window sills, go with paint.

[Dan Lautner]

"The merit of particular woods, teak, mahogany, etc. is that they weather well without coating, turning a rich shade of grey depending on the variety. But they all breakdown under clear finishes, loosening even the best of finishes. UV absorbers in the finishes get "used up" and don't protect forever.

So, unless you are willing to devote a continuing chunk of time to maintaining these window sills, go with paint."


After thinking long and hard about these sills I may just paint the tops of the sills as they are not all that visible from the ground. You guys now have me worried about maintenance on my redwood siding. I'm going to use 1*6 T&G All heart redwood. I have been looking into exterior oil finishes from Cabot and Penofin. What do you think about finishing redwood siding like this. I have a lot of southern exposure on the house. I don't want to force my wife into sanding and refinishing this stuff every year

Thanks, Dan

[Rich Engelhardt]

Hello Dan,

I have been looking into exterior oil finishes from Cabot and Penofin. What do you think about finishing redwood siding like this.

Perfectly fine to go that route as long as you use a coating that has some pigment in it - such as an exterior semi transparent stain.
Personally, I don't care for exterior solid color stains, but if that's what someone likes, more power to them.

The pigments in the material block the UV rays to some extent. Not as well as a paint, but enough to prevent the rapid deterioration that clear coats allow.

The pigment also colors the wood giving a more even appearance.

Also - with redwood, you're dealing with a substrate that will literally drink material like stain to the point of almost saturation. Surface coatings, such as paint and/or spar varnish sit mostly on the surface. Stains OTOH, penetrate deep into the wood.

Go ahead and stain the siding. A good healthy coat of stain can deliver 4 or more years of decent service. My redwood fence still looked passable after nearly 8 years. Year 9, it looked ragged, and year 10 it defiantly needed something.

[Ben Grunow]

Is the spanish cedar as soft as red cedar is?

I worry about this if it is where people will be touching it or putting a drink on it or a flower pot.

[Floyd Harper]

About the same as douglas fir. It is harder than some red cedar. Softer than some. softer than teak.
http://www.sizes.com/units/janka.htm
This site has a list of woods and the hardness of them.

[Floyd Harper]

Spanish cedar also is really attractive. I was going to builder the case for a jewelry box out of bubinga, but when I pulled the board out it was twisted beyond repair. All I had was some spanish cedar. It turned out great.
Pictures attached I think.
The spanish cedar is the case that the drawers (bolivian rosewood w/ebony handles) are held in.
I just order a spanish cedar door and plan to make a matching mailbox and window planters.