# Patio door on concrete



## chandler48 (Jun 5, 2017)

If you were to lay in a 5/4" piece of decking, how much height would you have from it to the top of the rough opening? Adding small amounts of concrete over existing won't last very long, and you will be waterproofing it anyway using window/door tape and silicone. If you still have 82" after the wood, then you can fix the wood in place using powder actuated fasteners. We'll wait on the answers.


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## jeremy3s (May 1, 2017)

chandler48 said:


> If you were to lay in a 5/4" piece of decking, how much height would you have from it to the top of the rough opening?


The rough opening is almost but not quite 80 1/2" high. The new doors are supposed to be 79 1/2", but actual measurement is closer to 79 5/8". 5/4" Is going to be too tight.


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## Windows on Wash (Aug 30, 2011)

You could always take a concrete grinding tool and knock this down to a flat'ish surface and then add the 1x4" board (3/4") and have enough room.


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## Drachenfire (Jun 6, 2017)

Grind the concrete smooth. Put down a piece of self-adhesive rubberized membrane (available at Lowe's). On top of that install sliding door flashing. You can get a Jamsill Door Window Pan Flashing on Amazon.

This should provide a good seal and still give you room to install the door.


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## chandler48 (Jun 5, 2017)

I agree. If you are left with not enough height using the wood, the flashing pan is what you will want to use. I was trying to get the door at least up to the level of the flooring, but that may not be in the cards. http://www.homedepot.com/p/SureSill...ashing-Complete-Pack-HDO-6-625S-040/202074145


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## jeremy3s (May 1, 2017)

So I am for sure going with a flashing pan. 

I'm going back and forth over the need for a piece of wood as well just to take the pressure off the pan from any high concrete spots. Would there be a problem using 1/2" pressure treated plywood?



Drachenfire said:


> Grind the concrete smooth. Put down a piece of self-adhesive rubberized membrane..


Would I want to use anything like construction adhesive with this? I guess I just don't see this sticking to the concrete.


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## chandler48 (Jun 5, 2017)

Yes, grind the concrete, apply a good quality silicone up the side and along the run of the door, before you install the pan. The silicone will seal the elements from entering from below.


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## Drachenfire (Jun 6, 2017)

jeremy3s said:


> Would I want to use anything like construction adhesive with this? I guess I just don't see this sticking to the concrete.


It is self-adhesive on the bottom so you would need to apply sealant on top between the membrane and the flashing.


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