Easiest installation of any expansion joint replacement product


Expansion Joints

Trim-A-Slab is available in four sizes, 1/2", 3/4", 1" and 1-3/8" - and also in three colors, cement grey, walnut, and black. Trim-A-Slab sizes follow THE GAP THAT YOU ARE FILLING. For more information on specific products choose from the selection below.

>> Trim-A-Slab, 1-3/8"

>> Trim-A-Slab, 1"

>> Trim-A-Slab, 3/4"

>> Trim-A-Slab, 1/2"

Trim-A-Slab is a replacement for rotted and old wood typically found between slabs in driveways and sidewalks. This wood was used during the slab construction, and is part of the ‘formwork’ used to define the size and shape of the slab. Once the cement had cured, it remained to accommodate movement of the slab as it is heated in summer and cooled in winter. This wood then functions as an ‘expansion joint', but not very well.

Typical Slab Construction

The problem is that what makes good formwork does not necessarily make a good expansion joint.  The elements conspire to attack and destroy the wood, even if it was a rot resistant variety or pressure-treated to resist rot.  Moisture allows bacteria to attack and break it down, movements open gaps which allow dirt and roots in, and eventually, the formwork looks a lot more like potting soil than wood.

What wooden expansion joints are faced with

Unless treated with weed-killers, your driveway can easily look like the one pictured below.  Of course, chemical weed-killers are also undesirable, as driveways are almost always very close to storm drains.  The best way to keep chemicals out of your local watershed and fisheries is not to use them at all.

A driveway gone bad




Trim-A-Slab is made from a rubber-like material that flexes and holds itself into the gap between concrete slabs. It is immune to rot, moves with slab expansion and contraction, and is not affected by moisture.  It provides a redundant barrier to weed growth, and most importantly, does not trap dirt and debris like wood and other less flexible products.  It will make your driveway easier to keep clean.


Trim-A-Slab is available in four sizes, 1/2", 3/4", and 1-3/8" - and also in three colors, cement grey, walnut, and black. Trim-A-Slab sizes follow THE GAP THAT YOU ARE FILLING. For more information on specific products choose from the selection below.and also in two colors, grey and black. Trim-A-Slab sizes follow THE GAP THAT YOU ARE FILLING. For more information on specific products choose from the selection below.

>> Trim-A-Slab, 1-3/8"

>> Trim-A-Slab, 1"

>> Trim-A-Slab, 3/4"

>> Trim-A-Slab, 1/2"


Trim-A-Slab is a patented design (US 8,132,380), and is intended for slabs with radius (rounded) edges, and will fit and stay just below the surface without any special preparation   The exposed surface is slightly recessed, and is resistant to damage from foot and auto traffic.

Installed Trim-A-Slab

The clean, finished appearance is something your family and your neighbors will notice right away. It’s virtually maintenance free, and in case you need to run wires across your driveway for Christmas lights or an irrigation system, Trim-A-Slab can be removed and re-installed, no problem.

Trim-a-slab comes in black, cement grey, or walnut. Choose black for the lowest maintenance or an accented appearance. Choose grey to blend in. Walnut goes well in stamped or stained driveways. Please note, Walnut and Grey will show tire marks after a while, but they clean up easily with soap and water. All are guaranteed for up to 10 years for structural integrity, so whichever look you prefer, you can be sure it will last.

 Trim-A-Slab is available in pre-cut rolls, which weigh less than 20 pounds each, so if you do want to install yourself, it’s easy to handle. Visit the installation page for all you need to know about installing Trim-A-Slab.  If you aren’t the do-it-yourself type, the installation page for a list of installers, who will take care of the whole job for you.

Cost Comparison


When it comes to expansion joint repair, there are a few options to consider. You can replace the wood with new wood, replace it with caulk, or replace it with a filler strip. Of these options, wood is clearly the worst. It is the hardest to fit back into the space, and there is no easy way to secure it. Any warping tending to lift it out of the joint will create a protruding trip hazard. All the same problems explained above with new wood remain as well, so weeds will establish themselves in the cracks, and in a few years the process will have to be repeated.

The next thing to consider is the caulk-like repair. This method has more than a few issues as well.  The material will fill the void space completely, which is good, but any subsequent caulk shrinkage or movement of the slab to open the joint will pull the caulk from the concrete and create a vertical crack.  This crack then fills with dirt, debris, and finally weeds.  The caulk-like fillers simply don’t have enough compliance (which is pure stretching) to fill an expanding gap.

These materials also must be installed with some planning and skill.  The depth of the evacuated joint must be closely controlled in order to be able to correctly estimate the amount of stuff needed to fill the joint.  This can be done by back-filling the joint with sand, or by installing a filler strip which is pushed down to the desired depth.  The filler strip is fairly easy to use, but the finished expansion joint is actually poorly supported, and can collapse down into the joint over time or due to foot or wheeled traffic.  Lastly, the caulk-based repairs are a viscous sticky liquid which must cure.  This means it must be installed carefully, and in a controlled manner to get a nice end product.  The following instructions are from a tube of name-brand concrete and mortar filler and sealant:

Apply in temperatures over 40 F

Do not apply when rain or freezing temperatures are forecast

Joint should not exceed ½” wide by ½” deep

Allow to cure for 24 hours before direct exposure to water

Completely dry in 7-14 days

These are a lot of restrictions, and in addition, if your driveway is sloped, the material will run downhill, and may be difficult to keep where you want it.

Caulk Fill

The best method is to re-fill the gap with a 'compliant filler strip'; Trim-A-Slab. A compliant strip, which is compressed when installed, is able to expand back to a larger size when the slabs move away from each other. Neither wood nor caulk fillers can do this. The more compliant the strip, the greater the range of motion that the joint can have without becoming loose and allowing dirt and weeds to accumulate. Trim-A-Slab is very compliant, so much so that it takes only 4 sizes to fill gaps from 3/8" wide (about half the diameter of a dime) all the way up to 1 and 5/8" wide. This compliance also makes Trim-A-Slab incredibly easy to install. Most of the time, it can be installed by hand.

 The table below summarizes the cost, as well as some of the other factors which should be considered when deciding on a repair for your expansion joints.



As you can see, Trim-A-Slab is a clear choice for families that lack time, tools, skill, or the inclination to take on a DIY project.  Trim-A-Slab installs fast, about a foot per minute.  A typical 2 car driveway with 100 ft of expansion joints is done in about an hour and a half.  It will take about 37 tubes of caulk to do the same job!


Price/Order Information

Trim-A-Slab is available in three colors, cement grey, walnut, and black, at hardware stores in many parts of Texas. Mail-order is available as well; see out 'Store' tab, above. Trim-A-Slab is also available by the foot for direct pick-up at our League City distribution center, or through a distributor; please see the 'Distributors' tab for an up-to-date map of retail locations.

Current MSRP is given on the product data sheets, and at the online store. Because Trim-A-Slab is a oil-based product, price does fluctuate. Please refresh your browser to be sure that the most current data is being loaded by your computer.


Just how easy is it to install Trim-A-Slab?

Trim-A-Slab pushes in by hand, or can be stepped on to install. It does not need to be driven or hammered into place. We have had Trim-A-Slab installed by kids under 10 years of age.

Do I need to use some kind of glue; how soes it stay in?

Trim-A-Slab grabs the inside edges of the slab during installation, and hold itself in. No glues or joint prep like back-filling is required. The 3/4" size is actually over 1" in width, so that when it is installed in a 3/4" gap it is in compression and squeezed down to the 3/4 inch size.

Can I get help installing Trim-A-Slab?

Absolutely. You can use one of our installers, or you can pick up some Trim-A-Slab yourself and use your preferred handyman.

How do I get the wood out?

This can be the hardest part if the wood has not rotted. We recommend prying it up from the ends rather than from the middle. If a piece is inaccessible from the ends, drill a few holes into it and place lag bolts into the wood, and pry up on those. 

I ran into a nail, how to I get that out?

If you run into the occasional nail, a blow to the nail using a pry bar will typically shear it off or bend it out of the way. Trim-A-Slab is very compliant and can be easily cut with shears, so it is not necessary to remove all obstructions. You can cut away a portion of the underside of Trim-A-Slab to clear the obstruction.

Is there any real difference between the black, grey, or walnut colors?

All our products are made from flexible PVC, with UV inhibitors. Black is the choice if you want the lowest maintenance, as it will not show tire marks. Black will also make the concrete 'pop' a little, and make it look a little cleaner and brighter. The grey material is color-matched to concrete, and will blend in with clean, dry concrete. After a rain, concrete darkens, which will make the grey appear to stand out and look lighter than it really is. While the grey color will show tire marks, it is easily cleaned with soap and water. Walnut blends well with many colored concrete, stamped concrete, and exposed aggregate driveways. Walnut is similar to grey, in that it will show dirt, and is as easily cleaned.

What size do I need to use?

Most residential driveways and sidewalks were poured with a 1x4 or a 1x3 board used for the forms. These boards leave a gap about 3/4 of an inch wide, and will be by far the most common size. Use 3/4" Trim-A-Slab in these cases; you can make sure using our 'Sizing Guide' available on every page in the lower right side, in the 'Files' text box. 3/4" Trim-A-Slab comes in up to 50 foot long coils. This is the most likely way you will find it at retail stores.

In some cases, slab motion may have been significant, opening up slab gaps to 1" or more. Trim-A-Slab 1" is best suited for these applications, and it accommodates gaps from 7/8" to 1-1/8". 1" Trim-A-Slab comes in up to 25' continuous lengths.

On the west coast, 2x4 lumber is often used as form boards. Trim-A-Slab 1-3/8" picks up where the 1" size leaves off, and will accommodate up to 1.5 inch gaps. 1-3/8" Trim-A-Slab comes in up to 25' continuous lengths.
One other type of expansion joint is also encountered, and it is based on the 1/2" wide 'fiber-board'. Fiber-board looks like an asphalt-impregnated fibrous product, and we produce the 1/2" size to replace these joints. You will sometimes find these joints at the intersection of the driveway and the garage.

What kind of warranty is there on this product?

Trim-A-Slab is currently warranted for up to 10 years. Trim-A-Slab will not crack, get brittle, or be adversely affected by heat or cold typical for a driveway anywhere in the US. Trim-A-Slab has been use from Minnesota to Florida.

Where can I purchase Trim-A-Slab?

The 'Distributors' page has a map of stores that stock Trim-A-Slab. We are most often found in local hardware stores, such as Ace, Tru-Value, and Do It Best. The 'Store' page will allow you to purchase direct, and have it shipped to your door.


Download any of the files below for your reference.

Sizing Guide - 125kb PDF

Trim-A-Slab, 1-3/8 - 179kb PDF

Trim-A-Slab, 1" Product Info - 143kb PDF

Trim-A-Slab, 3/4" Product Info - 168kb PDF

Trim-A-Slab, 1/2" Product Info - 129kb PDF

Shipping Estimate - 194kb PDF

Mail Order Information - 335kb PDF

Expansion Joint Primer - 30kb PDF

Installation Manual - 1.8mb PDF