Out side window sill

[JTTHECLOCKMAN]

Anyone replace a rotted outside window sill?? What is a good wood for this?? Any do's and dont's??

[daddo]

I was going to use treated wood, but it shrinks too much unless you have time to store it and dry for a month or two and I didn't have that much time, in fact I had only an afternoon since it was during my busy season and I was working long hours and weekends. i used what I had on hand. Yellow pine would have been a better choice.
 I cut back 4 to 6 inches from the rot and replaced it all.
I found it when I pushed my finger through the paint.
 A sawzall can be used to cut the nails between boards to get them out and a lot of chiseling.

Sealed it good with caulk (Used caulk to coat and seal all the ends of the boards) and two coats primer and three thin coats of paint. I used galvanized nails and coated screws. I also insulated what I could, but it's an old house. Took about 3 hrs, then painting inside and out.

[John Mihich]

Did it last fall on an 1850's house.  I used select 3x8 pine.  They have been doing it for decades.  The big thing is to use good paint.  I guess you can use cyprus or cedar.

[Robert Adams]

My preferred sill is a concrete sill. A little harder to find but easier to do than a typical brick sill and no leaky mud joints. Concrete sills can also be used on sided houses as well but I don't have much experience with those as siding isn't allowed by code in most citys here.

[Stwood_]

I've used either treated or redwood.

[JTTHECLOCKMAN]

I've used either treated or redwood.

I have heard the same as the above post about treated lumber shrinking when dried so will stay away from that. I will be painting white for now but will eventually be covered with aluminum when I get house sided in a couple years. Thanks all for the replys.

[K. L. McReynolds]

https://www.homedepot.com/p/Woodgrain-Mi.../206178841

[JTTHECLOCKMAN]

https://www.homedepot.com/p/Woodgrain-Mi.../206178841

That is an indoor window sill or stool as it is called. I have to do the outside where it rotted.

[rfd8w5]

Anyone replace a rotted outside window sill?? What is a good wood for this?? Any do's and dont's??

Pressure treated wood is Yellow Pine. Unless you have a historically significant house with all the "rules" that go with it, one of the modern alternatives to wood is your best bet. Azek and all the other vinyl product work very well, take paint and caulk and will never rot. They work just like wood too so no special tools or techniques are required. Some common molding profiles are available including preformed sills and sill nosings. Use the appropriate glue for the brand you choose to avoid warranty problems. A product called White Hot also works well.

[mike4244]

Anyone replace a rotted outside window sill?? What is a good wood for this?? Any do's and dont's??

Any wood that does not easily rot. I have used Luan ,Cedar, White pine , Yellow pine, and White oak. I used Poplar when on one house when I was young and did not know that it rots quickly. Two years after I installed 4 window sills  installed with poplar.I had to replace them at my cost. If you use oak, make sure it is only white oak as red oak rots almost as quick as  poplar.
mike