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Threshold support


guy48065's Avatar
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06-06-13, 11:52 AM   #1  
Threshold support

I just replaced a 32" front entry with a 36" fiberglass door. The remaining issue is the threshold. The old door had a thick wood threshold that went down to the slab porch--which looks to have been poured after the door was installed due to the rough and unevenness under the threshold. The new door has an aluminum one that is thinner and is almost 1" above the slab and unsupported past the sill. I shot a small bead of foam in there to protect against bugs & water.

I'm thinking a cement base tucked under the aluminum with a beveled edge around the perimeter might be the best solution to this. Opinions?

 
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06-06-13, 12:25 PM   #2  
No pix, but pull out that foam and put in silicone. Foam doesn't stop water well, it only insulates. Is there a way to configure a wooden threshold support. Of course the cement one will work, too, if you have the patience to build it.

 
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06-06-13, 12:52 PM   #3  
I find that using concrete usually means it will be too thin and have no lasting value. I use pressure treated wood and allow it to stick out past the threshold by about 1/8 inch. I like full support for a threshold, you never know when a refrig or furniture will be wheeled in and out.

 
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06-06-13, 02:54 PM   #4  
Support is why I was trying to avoid wood. As mentioned the area under the old threshold is very uneven (whatever concrete slumped into the space under the old threshold). It's tapered from a hair over 1 inch to about 3/4 across 36". I would need to eith hollow out the new threshold a little at a time till it slid in place or try to grind the concrete flat.

I was concerned that a concrete threshold 1" thick might not last...but aren't there special mixes or additives that help thinner builds to stay in one piece? I watched pros skimcoat a spalled set of stairs & that lasted decades.

 
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06-06-13, 03:07 PM   #5  
But their skim coats aren't supporting anything. You will be supporting that refrigerator or large neighbor who comes over to watch the game. How far does the threshold protrude over the old pour? How tall will the threshold fill be from floor to bottom of threshold?

 
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06-06-13, 03:37 PM   #6  
Just 3 weeks ago I had to grab a 4 x 4 pressure treat, cut to length, then cut it to width and height, and then scribe it to fix the rough concrete base including a large two level crack. It took some custom cutting, but the cuts don't have to be pretty because you make sure the pretty side shows. And I had to do tapered cuts also. You want the showing face to look good, and remember that the threshold is a straight flat bottom. Then I had to take that piece of wood and cut a 45 degree angle at the back bottom because the concrete lipped up a little. And I caulked before putting the wood down. Yes it is a little work, but not too difficult.

I wouldn't have felt comfortable using concrete unless it got drilled, epoxied, and pinned. And for such a small area???

 
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06-06-13, 04:53 PM   #7  
Please don't use concrete.

I like to use solid composite decking for "sill nose aprons" to support the front edge of aluminum door sills. It won't rot and won't warp. Sometimes you can find a grey deck plank that when ripped down to the right size will look pretty good under there. I usually will just friction fit them, and use a sealant like BASF /Sonneborn Sonolastic NP1 to hold it in place.

The Menards stores in our area sell various kinds of deck planks in 4 footers that are perfect for this. 1" thick is the usual thickness that seems to work well. You don't really want a ledge that will catch water in front of the sill nose. It's nice if it's flush or just a hair behind.

I would definitely grind the concrete (4 1/2" grinder and diamond blade... u don't really need to use a cup grinder, but it would probably be easier/better) to give yourself a smoother surface, and the taper isn't too hard to cut, either on a table saw or with a skilsaw.

 
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06-06-13, 05:36 PM   #8  
I'm with Xsleeper on this one.
Modern codes would call for at least a 4" drop under that threshold, some places it's 6".
Reason being water is sure to find a way in and rot out the subflooring, rim joist, bottom plates, sheathing.
No way should what ever you use ever stick out past the treshold, if you do you just made a funnel to direct the water behind it.
I've made thousands of dollars from some builder building it that way.
I use 3/4 Vinyl lumber instead of decking but it works the same way.

 
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06-06-13, 06:19 PM   #9  
And that is a difference between east coast and west coast building. We don't get as much rain as you guys do. I even build decks so you can step right outside, not down. It's pretty standard out this way. And also, I caulk that lip before I paint the new wood. And a little 1/8 inch lip at a door with a good overhang -- I haven't seen any problems with that yet.


Last edited by Re-mdlr; 06-06-13 at 06:41 PM.
 
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06-07-13, 07:01 AM   #10  
How fast does a diamond dry blade in a 4" grinder remove concrete? I really don't want to spend half a day trying to knock down this 36" wide ~3/8" high lip where the slab was troweled around the old wood threshold. This lip (and the hollow behind it) seemed a hurdle for sculpting a wood threshold but an advantage in anchoring a concrete or mortar one.

Is there anything 20th century? Some injectable product that will fill/seal/support under the aluminum?

IF my only real option is a solid object like wood or pvc I'm probably going to have to take a bunch of measurements and bring them home to sculpt it in my shop. I don't have much in the way of tools to work with up there. Sounds like a bandsaw & a die grinder could come in real handy.

 
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06-07-13, 07:08 AM   #11  
It's anyones guess how, and what to do without a picture.

 
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06-07-13, 09:17 AM   #12  
While "guessers" do serve a valuable role in bumping a topic to keep it alive, hopefully eventually someone will post a solution from experience.

 
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06-07-13, 03:28 PM   #13  
How fast does a diamond dry blade in a 4" grinder remove concrete?
Fast. I wouldn't grind it to make it 1" on both sides... just grind it enough to make it flat and straight, so that you can cut a perfect 3/4 to 1" taper. Cut the taper at home, take the grinder with you, and grind it until it fits.

No reason to fill in the hollow sunken part with anything unless your sill nose apron wants to drop down into a hole. If that's the case, just buy a bag of vinyl cement patch to fill in the hole, prior to installing the tapered sill nose apron.

 
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06-07-13, 04:30 PM   #14  

While "guessers" do serve a valuable role in bumping a topic to keep it alive, hopefully eventually someone will post a solution from experience.
We combined, have offered solutions. We also have asked for pictures so we aren't "guessing" blindly. This isn't going to get into a spitting match, or I'll close the thread.

 
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