# How to finish this part under a door sill?



## chandler48 (Jun 5, 2017)

Depending on how much the threshold sticks out (usually 1") we install a piece of 5/4" pt lumber there to add support to the threshold end. Sometimes it will need ripping depending on how tall the opening is. Install with 2" GRK exterior finish screws.


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## GlenDIY83 (Mar 14, 2018)

Is 5/4" a type-o? I'm assuming you meant 3/4"?
I could just be a noob too... Lol


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## chandler48 (Jun 5, 2017)

If the threshold sticks out an inch or more, which is normal a 5/4" (full 1" thick board), as in decking boards would suffice.


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## Nealtw (Jun 22, 2017)

Actually measures 1 1/4" thick.
https://www.homedepot.com/p/5-4-in-x-6-in-x-8-ft-Premium-Kiln-Dried-Cedar-Lumber-MR0510508/202302534


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## joecaption (Nov 30, 2011)

If the door was installed correctly the threshold should have been sticking out at least the 1" Chandlers talking about, yours is not.
No way would I use pressure treated wood for this for several reasons!
The new pressure treated wood is treated with copper and will form electrolyisis when in contact with aluminum.
Pressure treated wood would be soaking wet and take months to dry out, it does not like to hold paint, I only use solid stain.
Anything sticking out past the threshold will act like a funnel and direct water under the threshold.
That threshold was made with a 3/4" slot under it to slide in a 3/4" thick kicker support under it, with it set so far into the open it's not going to work.
Also the door was not set in a sill pan which is the best way to do it, at least they could have added the needed flashing.
http://jamsill.com
Just want to make it look better about the only way now it to paint the concrete.
I've been paid many thousands of dollars over the years repairing all the inside damage done from sliding doors installed like yours.


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## GlenDIY83 (Mar 14, 2018)

Ha! Turns out I'm just a noob. Thanks for the great explanations.

So joecaption, you have experience with fixing this... How do you make a judgement call as to whether or not a repair is necessary? I'm going to remove that concrete step... Who knows what I'll find. How much rot/water damage is too much?


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