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qrs 06-07-2010 11:29 AM

Expansion Joint Filler
I have an expansion joint that I would like to fill. The EJ is located at the point underneath the roof of my carport where the concrete carport slab meets the concrete driveway. Although this is under the edge of the carport roof, this EJ does get wet from a hard or wind driven rain.

This EJ is almost 3/4" wide and is quite deep. I am thinking that I can use some sand to fill in the bottom first and then use a backer rod before applying a type of sealant.

Lowe's has two things that might work.
1) DAP Concrete and Mortar Filler and Sealant - $4.16 per 10.1 oz tube.
2) Commercial Grade Quikrete Polyurethane Sealant (Self-Leveling) - $6.76 per 10.1 oz tube.

Any suggestions?
Thanks in advance.

slownsteady 06-09-2010 01:04 PM

My first reaction is; if you fill it with a concrete product, then it can't expand. Probably not a good idea. I don't know these products well enough to judge whether they have enough flex to do both jobs (allow expansion and fill the gap). I remember a while ago that guys would use roof shingles cut to fit & stuffed into the joint, although I suppose a silicone product would work better.

qrs 06-09-2010 06:05 PM

Exactly...I do understand that whatever goes in there has to be flexible. The tar like stuff that they use for streets would be great, but I am looking for something that I can do myself without creating a huge mess. Thanks!

slownsteady 06-11-2010 02:05 PM

How about driveway sealer on top of sand/gravel?

itsreallyconc 06-15-2010 04:04 AM

backer rod & sealant alone is the correct method,,, ask me - have done 100s of miles of that item,,, IF you feel the need to insert anything under the backer rod, use vermiculite

RnDGuy 08-16-2010 08:51 PM

There are some new expansion joint fillers on the market now in the Houston area - faster, cheaper, and way better looking for a DIY install, as almost no skill is involved. These fillers are made of rubber or flexible PVC, and generally come in a roll in a couple of different colors. Trim-A-Slab works for replacing 1x4 expansion joints with rounded edges. Just clear down to about an inch and a half, and press in, no prep needed. There's another one if your joints are bigger. It goes by Slab Gasket, and may need sand under it as a prep.

Nestor_Kelebay 08-17-2010 12:46 AM

Maybe ignorance is bliss, but I'd be asking myself whether it's important to keep water out of this expansion joint.

You live in Louisianna, where you get plenty of rain, but it's rare for the ground to freeze in the winter time. So, frost heave is extremely rare.

Also, if your driveway and concrete garage slab are surrounded by lawn, then the ground/aggregate under the slab and driveway are going to get wet with or without water proofing this expansion joint.

So, if caulking the joint isn't going to provide any benefit cuz water is going to get under that slab anyhow in a rain, then why wouldn't something like this be the best solution:

And, if push came to shove and you wanted to waterproof that expansion joint, a bead of that black plastic roofing cement would do that while sill allowing for movement of the slabs. And, that roofing cement would last forever since it would be protected from exposure to the Sun's UV light by the extrusion itself.

You can also get this same extrusion profile in aluminum and stainless steel. Just ask for "Tee Bar".

itsreallyconc 08-17-2010 04:39 AM

placing anything in a joint that doesn't allow for the expansion & contraction of conc will hasten the degradation of the jnt surfaces by encouraging joing spalling - here's how it works - just basic high school physics, btw,,, cold makes a liquid expand & solids contract - this means in an louisanna summer, the day's sun causes the slab to expand &, at nite, cooler temps allow it to contract,,, this results in the jnt width changing all the time,,, s/s jnt fillers don't allow any ext/contr therefore the jnt walls & surface edge near the jnt will eventually spall.

if anything else were better, i'd sure aci/icri would recommend it & state dot's/the feds/architects/engineers would be using them,,, we don't buy any joint sealant at apron stores - rather, seek out your local const cupply house where you can find closed cell backer rod & silicone jnt sealant.

the main reason for sealing a joint is to keep incompressible junk OUT of the jnts so when the slab expands, there's room for it to do so while not allowing ea slab to touch its adjoining slab therefore no grinding/spalling,,, the 2nd reason is to keep water out of the sub-grade & soaking the base therefore softening it & causing it to lose support capabilities for static or dynamic loading.

we have used s/s jnt systems INSIDE airport terminals ( newark, atl, ny, boston ) but, because the temp's controlled, slab size remains constant,,, if there're any other jnt sealing pro's on this forum, ask them,,, this should be enough to end this thread - if you're still in a quandary, remember its always YOUR driveway,,, the jnts in mine're sealed correctly.

RnDGuy 08-17-2010 11:02 AM

You won't see these used by many folks yet, as they are new. Here is one, installed.
It sits flush or below the slab surface, and won't affect slab expansion or contraction. It should be more dependable in case of a growing joint/shrinking slab. Polyurethane filler must be stretched, and it requires a good bond on both sides of the joint to keep it from delaminating, like this one.

itsreallyconc 08-20-2010 03:38 PM

that's a good idea however most residential driveways're installed by the cheapest guys the bldr could find meaning jnts're groov'd or formed rather'n sawcut,,, even IF they were sawcut, typically only a .125" ( 1/8" ) blade wouldn've been used,,, by now, everyone's gone & the bldr can't ee your house from his house :D that strip seal reminds me of neoprene jnt seal - at 1 time very popular for jnt sealing & resealing old jnts in good condition,,, $, ease of install, & method for resealing jnts knock'd neoprene out of the market.

the stuff typically used for crk-sealing on streets is usually astm - d-1190, astm - d-3405, or fiber reinforced asphalt cement,,, typically its applied at 370-400f & street sealers use squeegees or over-banders,,, you don't want that mess on your d/w,,, at least i don't

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