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· Registered
4 Posts
Discussion Starter · #1 ·
Hi everyone,

This weekend I plan on replacing a rotten/water damaged exterior threshold and the sill (the wooding piece beneath the threshold?) The door walks out onto the asphalt driveway. When I bought the house recently the driveway sloped towards the door and when it rained hard water ran under the door and into the basement.

I have corrected the slope issue on that area of the driveway near the door by building up that area with a trowel-on asphalt patch. Now i need to replace the damaged pieces of the door.

Can anyone walk me through this or provide and advice? I've never done this before. I am confused about what type of flashing to use underneath. I have heard people say that a stick-on flashing material should be used (looks like roll-roof underlayment in the how-to videos i watched on "this old"). I don't really understand where it would go though. Also, where should i put caulking?

I have attached some pics. I can add more if needed. I could probably get underneath the stairs in the basement and take a pic of the underside. I'm just worried about using proper flashing/caulking in the right areas so I don't have any water issues.

Thanks everyone! :thumbsup:

PS- the metal thing in the front is nailed to the sill underneath. i don't know what the previous owners did here but i'm sure it's not right.


· Too Short? Cut it Again!
9,639 Posts
Others my scream at this but flashing is usually a metal placed under building materials to establish the ultimate path for water to travel. Chimneys, skylights and so forth are flashed so that water, always heavy and seeking the lowest gravity point, is provided a path away. Same in your situation. Flashing itself has no real waterproofing capability as say a roof shingle does.

Caulk is the last of waterproofing processes and is added at the very end to fill in open gaps between construction materials that might allow small amounts of water in. Window glaze is a caulk of sorts and we use it to keep moisture from the glass panes to the wood framing.

Anyhow, In looking at your project, I cannot really tell from the photos the height of the difference between your interior floor and whatever the exterior surface is? It looks fairly steep and sloping and like someone has tried to threshold the angle a time or two before?

· Civil Engineer
5,832 Posts
Do not underestimate the time and effort for this project. I had a similar issue with my front door, and it proved to be more complex than anticipated due to more extensive wood damage than anticipated.

I cannot give you a blow by blow, unfortunately your door is probably different than mine. Here are a few tips.

1. You need to take the door and the frame off to make sure you remove all rotten or damaged wood. The rot may extend into the sill beam for the house, which would be a whole different issue.

2. I suggest you build or purchase a sill pan to go underneath the door sill. The pan is typically made of metal, either aluminum or copper is pretty common, and is sloped downward away from the house. The idea is to direct any water that attempts to get into the house from outside down and away from the house. In order to install a sill pan, you are going to need to remove the entire existing door sill, and the door jambs on either side.

3. Even with a sill pan, most places I have looked suggest an additional layer of ice and water shield underneath the sill pan. Defense in depth is no sin. You can use the ice and water shield underneath the jambs as well, however there are other products that work also, and I have seen metal flashing used up the jambs as well. When I did the flashing for my ledger for my deck, I used ice and water shield underneath aluminum flashing, which seemed to work very well.

4. As noted by previous poster, caulk is used at the end of the project to fill in small gaps, nail holes etc., and is not the primary water defense.

· Registered
2 Posts
Sill Pan pro

The sill pan underneath doors and windows is always a good idea. HeadFlasing with End Dams too. Take a look at you can buy SureSill on
From your photo, it looks like your door sill may be standing in the pool of water so even with the best installation you still may have problems.
You need to make:yes: sure any water around your door drains away quickly.
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