wood door sill question

[George]

I have a rotted door sill (among other things), a consequence of contact a concrete stoop. I've taken care of the stoop issues, and I need to replace stuff. The wood (oak) sills I've seen aren't exactly what I'm looking for, and I'm thinking whether to make my own. My question is, these undersides of these sills are grooved (lengthwise). Does anyone know why that is?

Thanks

[Terry Coombs]

Helps them to resist cupping and warping .

[Vic Smith]

I looked into this years ago, and basically got nowhere. Talking about thresholds and flooring. Sills are usually cut on the job to fit and aren't grooved. You hear speculation like reduced weight for shipping, and resistance to cupping. I like the "flexibility" theory. Allows for surface inconsistencies and won't crack. For a threshold I wouldn't worry about it. Same with a sill, but you want to use pressure treated wood for a sill, and level the concrete.

[clare]

To reduce the tendancy to warp - just like the bottoms of hardwood flooring are grooved.

[clare]

Regardless what wood you use over the concrete I would be installing a "gasket" - as simple as a layer or 2 of heavy building felt - or a layer of "blueseal" to keep the wood from directly contacting the concrete.

[HerHusband]

The bottom of the sill is grooved to reduce warping.

In recent years I have had to repair several doors with rotted sills. I chose to replace the entire door frame with a frame made of composite materials. Then I installed a jamsill pan liner before installing the new door frame.

I measured my door carefully (to the nearest 1/32"), door size and thickness, hinge sizes and locations measured from the top of the door, latch and deadbolt positions, etc. Then I took my measurements to my local Lowes store and ordered the composite door frame. They're not cheap, about $400, but unlike the wood frames they won't rot. The jamsill pan liner also ensures that any moisture that makes it's way past the door frame gets directed outside the building instead of rotting the subfloor.

Anthony Watson

[Mark]

Have you tried a real lumber store? The mills around here stock the oak sills, just like the ones from the old days. Tapered, grooved, notched, etc. All you need is the width of the door.

[stockbrokers]

I think if you are not finding one with exact measurement than you must try to make own because in this way you get exact sill with wood that you like and afford.