Where can I find ¾" x 2 ⅞" (~actual size) boards for window sill repair? Everything I find is ½" too long or too short!

Question

I'm working on my parent's home in order to get it ready to sell, and one project involves repairing a few sills on windows where stray raindrops through open windows have caused the (abysmally cheap MDF) material the builders used to swell up like a roll of paper towel. The MDF boards used to frame out the interior side of the windows measure ¾" x 2⅞", or .75 x 2.88.

The trim casing is easy enough to match; however, at both Lowes and Home Depot, the comparable pine or MDF boards that I've been able to find for the sills don't measure up properly.

At both HD and Lowes, I can find boards that are listed as 1x3 or 1x4. The 1x3s are actually ¾ x 2½, and the 1x4's are actually ¾ x 3½. Using either one of these puts me in a situation where the window casing/trim will either be unable to join against the shorter 2.5" board (or will leave a substantial, visible gap if nailed in), or (in the case of the 3.5" board) prevent the casing from resting flush against the sheetrock surrounding the window opening. Both of these are poor options and will look ugly. I'm trying to keep these repaired windows as consistent with others in the house as possible.

So, does anyone know where I can find ACTUAL 1 x 3, or boards close to ¾" x 2 ⅞ with much less than a half-inch variance from this as the listed spec? I understand that lumber has nominal vs actual sizing. However, these boards were clearly available somewhere, at some point in the last decade, such that they were used to frame all the windows in this house. Every store whose inventory I can search online gives me the same results, with an actual listed size of 2.5 or 3.5 inches.

I'm losing my mind a bit here. Any ideas? Am I missing something glaringly obvious?

Any help is greatly appreciated.

//

EDIT: It seems that tracking down an identical like product to match the manufactured boards that were originally used isn’t going to happen, at least not in the time frame I have available to help.

The way to go is to cut the boards to the specification; I get that. I was hesitant to go this route, because I am out of state away from my own tools, and have limited time to assist with several projects - path of least resistance and all that. I did inquire at the big box store if they could cut some lumber to spec for me, but alas, that place was out of commission, as someone had cut the power cable of the in-house saw in two.

SOLUTION: Tomorrow I’ll have the wood cut to spec at a place that’s equipped. Today, I’m focusing on the other projects.

To those who chimed in with confirmation and help that this was the direction to go in: Thanks.

Answer 1

A little extra work, but basically get the smaller dimension (3/4") off the shelf and cut to the other dimension (2-7/8") with a saw. A portable table saw is probably the easiest way to get consistent cuts.

This is either an excuse to buy a cheap table saw (and hopefully use it in the future on other projects) or you can rent a really good one for anywhere from a day to a week (or longer, but then you might as well buy).

Answer 2

You can spend hours and hours searching for boards cut to your exact specifications. OR you can saw them to the size you need and be done with the job.

Answer 3

True to most responses - the path of least resistance was to simply cut the boards to size. I was out of state and without my own tools - and never was able to find the actual manufactured product originally used on these windows; however, a good samaritan in the folks' neighborhood offered use of his table saw. Quick, and much less painful than trying to find the oddly specific dimensions in a pre-cut board. Windows reframed, problem solved.