Prehung Entry Door - Threshold Question


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Old 04-09-07, 07:39 PM
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Prehung Entry Door - Threshold Question

I have an older brick house. The entry door is original and I'm about to replace it. Currently there is what appears to be a 2x10 mounted as the threshold, which hangs out over the brick and acts as a step to get into the house. There's a piece of weather stripping mounted to that which seals the door when closed. I'm buying a prehung Pella door that has a small aluminum threshold. My question is, do I remove the original 2x10 wood threshold? I'd almost have to leave it there, otherwise there'd be a 2" gap to fill. All the walkthroughs I've found show the prehung being installed on a flat surface and not on step/ledge/subsill. Should I pull it up and put a piece of pressure treated wood there instead? Should it get wrapped in siding? All the houses in my neighborhood are the same so this has to come up a lot when hanging new doors. I've installed prehung interior doors, so I'm not familiar with the threshold. This is the only hurdle... well this and figuring out how to wrap the exterior portion of the trim in siding, if needed.

Any help is most appreciated.
 
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Old 04-09-07, 08:51 PM
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The sloped sill is actually nailed to the jamb of the door. So when the door jamb is removed, the sill will come up with it. Underneath the door you will likely find the uninsulated floor joists, and you will probably be able to see right into the basement/crawlspace. You can use this opportunity to install some blocking between the joists, and add some nice insulation under there.

But as to your question, yes, you will want to add a sill of some type. It could be pressure treated wood, but you would not use PT wood if you intend to have the sill covered with aluminum trim coil in the future. PT and aluminum do not play well together. Besides, aluminum wrapped sills get beat up quickly- they dent and the paint will scuff off and look bad. Your best bet is to continue to paint the new sill, IMO. You can use PT and let it weather for 3 months or so before painting. Old timers used solid oak because of its weatherability, so that's an option as well. Cedar and Redwood are also good options, if they are readily available in your area.

A couple things about the sill:

You'll want the new sill to be flat, and about 1/2" below your finished floor level. Your new door will need to sit flat on this sill. Take special care to install this sill perfectly level (in both directions!). If needed, shim below the sill so that it sits level.

The width of the sill will be determined by:

Wall thickness (measure from interior of wall to exterior of sheathing) plus your face trim (standard brickmould is about 1- 1 1/4" thick, but depending what you plan to use for trim, your thickness may be different) plus some overhang (minimum 1/4"... maximum 1" or so) as a drip edge over the bricks or siding below the sill. Add those measurements up to determine the total width of the sill.

Before you install the sill, prepare it by cutting an angle off the top front edge, so that the front edge of the sill (the part that will be exposed to the weather after the new door is installed) will be sloped. This is essential so that rainwater will drain away. Determine the width of the threshold on the new door. Mark where the front of the new threshold will be on the piece of wood you intend to use as a sill, and mark a line across the sill. Set your table saw at about 7-10 degrees, stand the sill up, and run it through, cutting up to the line you marked. Then belt sand that cut edge to remove the saw marks. Round sharp edges in front with 80-120 grit sandpaper. This will create a slope on the front of your new sill that will end just behind the front of the new threshold.

When you install the sill, be sure to apply several beads of sealant across the rough opening so that no air flows underneath the sill. The same thing goes for the door when you go to install it.

In many cases, you will also need to install an "apron" underneath the new sill. It's size varies depending on what is needed. You don't want the apron to stick past the front of the sill and catch water, so be sure that when you figure the sill overhang (as described above) you make the sill wide enough to overhang any apron that is needed below the sill.

Note: I've seen some guys leave the original sill in place, and add a shim across the front (to make the sloped sill "level" and to give the aluminum threshold support in front) but IMO, that looks hokey and often makes the door too high. Plus you don't get the chance to insulate below it and you'll keep getting that nice draft under the door.
 
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Old 04-10-07, 05:44 AM
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Wow. Well, based on your reply I might be outsourcing this one. Like I said in my original post, a normal prehung install sounds easy. What you posted, however, does not. Seems like there's tons of room for error. My second option was to have Pella install the door for me. Are the steps that you posted standard procedure for someone when the come to do the install? How can I ensure that they do it the correct way as you mentioned? I'd assume Pella would have quality guys that know this stuff. I'm not very experienced at hiring people to do stuff... I usually try and tackle it myself.

Thanks for the help.
 
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Old 04-10-07, 04:41 PM
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Well, maybe I made it sound complicated. It really isn't that bad. And there's no guarantee that some installer would do it the way I described as if "my way" is the only "right way" to do it. A variety of installers would do it in their own unique way. I simply described how I envision it.

You are right that one could assume that Pella would have qualified installers who have done this a thousand times before.

If you're handy at all and have the tools to tackle it (reciprocating saw, table saw, etc) then I'd say go for it. If nothing else, it will be a learning experience for you. If you hit a snag you can always ask for advice here, there are many people willing to offer you a hand.

Worse case scenario: you tear out the door and have to put a piece of plywood over it for a day or two while you figure it out or get the materials you need.
 
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Old 04-11-07, 02:02 PM
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Got my quote lol. I retract my previous statement about outsourcing this job. I'll be giving this one a shot on my own. Holy cow.
 
 

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