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Exterior Garage Door Sill Problem

I had someone hang a fiberglass side door. Although the jambs that frame the opening connect to the sole plate, there is and was only concrete under the swinging area of the door.

That concrete cracked when the tenaciously-adhered threshold of the old door was pried up. The installer used rapid-set cement to replace it and form a lip out onto the outside brick landing. The rapid-set cement is soft and cracked. Even though the angle of the landing makes everything look cockeyed, the rapid-set actually does fall off level to the largest extent of about 1/4" under the aluminum threshold at one end of the door.

Although I can demo the front lip of the rapid set back, unless someone has a fine idea about how the defective front lip of the rapid-set sill can be replaced with something that will be level and hold up, the door is going to have to come out. And a new sill poured. However, if someone does have a solution on those lines that allow me to keep the hung door in place, I'm all ears and praises.

Assuming the door needs to be removed and the rapid-set sill demolished, I'll need to pour a new sill.


*What materials, additives and reinforcement lead to a result with high water resistance balanced against an early curing time allow door reinstallation?

*How thick does the new cementious (or other material) of the sill need to be
for durability where it meets the aluminum door threshold given that it has to slope about 2 inches to a horizontal descent to the exterior brick landing?

At the current door height, a poured level sill would be @.5" on one end and @1" on the other at the other of the aluminum threshold before sloping to finish in a smaller snubbed edge on the cockeyed exterior brick landing. If the header is raised, the new sill could be taller. If the header is raised significantly and the door along with it, the new sill might be fashioned to have a thicker cantilevered lip over the brick landing.

*Would there be a bonding material to improve the sill lip and brick landing contact?

That is about it. Anyone with responses, tips or a better idea is welcomed with advanced thanks.
I'd love a fix that didn't require removal of the door but haven't had that inspiration arrive.

Pictures of the tragedy are attached.

Re: Exterior Garage Door Sill Problem

I Googled and it seems you can't attach pictures to a post until you've logged
ten posts. Oh well. If anyone has a way around that, please tell me. Thanks.

Re: Exterior Garage Door Sill Problem

First, make sure you're logged in; then send an e-mail or private message to JL McDaniel, the site moderator with your uploaded photos & he will post them for you.


Re: Exterior Garage Door Sill Problem


Thanks for the effort. I tried. According to the denial notice received, I have to push my 10 post count to 20 before any pms can be sent to other members, so no go.

If people could just respond to the list of questions about selecting materials and constructing a
concrete/cement or other sill in this situation, that would be very welcome and helpful.

Re: Exterior Garage Door Sill Problem

Thanks to the insight of another, I see a solution here shifting. A kind contributor observed that the brick landing where the bad pour of rapid-set cement ended in an attachment had it spanning a joint from the garage slab making it liable to crack. Makes sense to me.

So, either the the overhanging lip of the aluminum threshold had to act as a drip edge (which it seems inadequately wide for) or something had to be placed atop an upright pour under the aluminum threshold to act as a drip edge. A white oak sill was suggested. It would be sturdy but not maintenance free. Plus, it may be excessively thick and require raising of the header to raise the door, something I'll check on tomorrow.

My first thought was a thick plastic. I looked at Azek but some complained about movement if not secured at intervals. Here, it would be trapped by the aluminum threshold and the concrete pour. Does anyone have a better candidate material that would work in the position under the threshold as a sill/drip edge that would be stable, sturdy, durable and not require maintenance in a thinner thickness than a wooden door sill?

Re: Exterior Garage Door Sill Problem

I'm now looking at cutting a 1/4" thick aluminum door sill and placing it under the aluminum threshold after I've ground down the ridge underneath which would prevent it from lying flat.

My idea is to affix the sill to the concrete with tapcons and a flexible, waterproof and adhesive polyurethane sealant.

If I raise the concrete pour mounting the sill, I might be able to cantilever and extend the lip of the sill about .75"-1" into the air over the exterior brick landing.

The aluminum door threshold should sit level on the sill and join to it with a waterproof, flexible and adhesive sealant polyurethane.

Pictured is an old piece of aluminum door sill showing the approximate position a new piece would occupy in relation to the door, threshold and brick landing. **For some unknown reason my 2.14 MB JPEG picture is refused as an invalid image file. Sorry.**

Another thought is to rip out the brick landing an replace it either with a new brick structure that is level and angled away from the door or use concrete to do the same.

Comments, thoughts or any suggestions correcting or improving the result here are great.

Re: Exterior Garage Door Sill Problem

Does anyone have experience with a stone sill? If the stone is too thick, I'd have to raise the header and door. What type of stone would be strong enough starting under 1" in thickness to span across the dissimilar materials of the stucco and brick landing while being able to have a slight runoff slope ground into it?

Any other possibilities or thoughts?

Since I don't

Re: Exterior Garage Door Sill Problem

Maybe it's just me, but from the start I cannot quite understand your situation based on your words, which have digressed into totally different concepts with me still not understanding what's going on. If you put pics on-line where we can see them, you can post a link in plain text so we can copy and paste it into our browsers. Just break up the text like this:

https:// advice.!thisoldhouse. com/!newreply. php?p=288513&! noquote=1

and say to remove the exclamation marks and spaces. That will show up.

Now more to the point- is the walkway lower than the garage slab? Is the walkway foundation poured separately from the garage slab? Am I understanding correctly that one side is 1/2" lower and the other side 1" lower? What is currently under the door threshold (I'm thinking it was the quick-set concrete) and can it be easily chipped out?

The reason I ask is that this may be an easy fix by using high-strength grout such as what is used under steel columns in industrial work. This is shoved into the gap between the steel and the foundation, sets very fast, is intended to be used in compression (such as under a threshold) and maintains strength even in very thin applications. "Sika" grout is the brand we most used here but I'm reaching back 25 years into memory so I can't offer too many more details about the product. From mixing you have about 5 minutes or less till it sets up so make small batches and use a trowel, sticks, or whatever to push the grout off a shovel into the gap underneath till it is filled completely, then finish the exposed edge as you would concrete. Work fast and if the mix starts setting up toss it and make another batch. You can pre-coat the area with a concrete bonding agent for better adhesion. this stuff reaches full strength in 24 hours and then you can drill it for fasteners if you wish. Best to experiment with this to get the mix right before tackling the project- it sets up unbelievably fast like Bondo.

Now if the walkway is separate from the slab (no shared foundation) then whatever you use to bridge that gap will crack if one settles differently than the other (and it probably will) so what you may want to try is to grout just to the edge of the threshold, let that set up, apply a thin film of silicone caulking tooled flat, then once that has cured form the 'ramp' transition using this product separately so that it moves with the walkway independent of the garage which should prevent cracking. Or if the slight difference of 1/2" with a 1" step doesn't bother you, you can just leave it as-is though that might not meet code requirements where you are. Though I see it done all the time, when two foundations meet you really need to tie them together with drilled-in rebar or smooth rod epoxied into the thicker or first-poured foundation so that they rise and fall together which will prevent cracking between the two.

Hope that helps and hoping to see pics soon.


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