How to Repair Cracks in Concrete Floors

Cracks are the most common problem in concrete floors, concrete driveways, patios, pool decks, concrete roofs, airport runways, etc.

Click to enlarge!

Beside the seepage of water, vapor, and radon gas into buildings, some other problems with cracks:

• Trapped water destroys flooring materials and may cause mold infestation.
• Water causes rusting of reinforcing steel and destruction of the concrete.
• Water leaches out concrete and causes efflorescence (whitish deposits).
• The freeze-thaw cycle widens the crack.
• Vehicular traffic crumbles the edges of cracks.
• Further elongation and yawning of cracks due to natural movement of concrete.
• Propagation of cracks into rigid flooring tiles or concrete overlays.
• The cost of repeated repairs.

RadonSeal CrackWeld Concrete Floor Repair Kit fills the full depth of cracks with a rigid compound that is stronger than concrete. It provides to contractors and homeowners the state-of-the-art method for permanent repair of cracks, spalls, or holes in concrete slabs. (Not available in stores, shipped directly from the factory.)

About the old crack “fixes”

Caulking the crack is cheap and easy but short-term. The caulk will not last in traffic. Water wicking through the concrete or trapped water vapor will cause efflorescence and will weaken its bond to concrete. After a couple years, the caulk can be easily peeled off.

Hydraulic cement is a temporary fix only. It is fully waterproof but does not bond well to concrete – that’s why you have to route out an inverted V-groove to hold it in place. However, concrete continually moves, shrinks and expands which loosens the stiff hydraulic plug. After a couple years, the crack will gradually start leaking again.

Why use CrackWeld for concrete crack repairs

Video – CrackWeld DIY Kit

RadonSeal CrackWeld is a two-component compound. When ejected out of the cartridge through a mixing nozzle, it fills the crack and quickly cures. Similar to epoxy but only 1/10 as thick and routing is not needed. It bonds with sand into an indestructible, impermeable mass inside cracks, spalls, or holes. Water, vapor, or gases cannot penetrate. It is also a structural repair – it stops the crack from further movement.

The CrackWeld slab repair kit makes permanent crack repair quick and easy:

• Very low viscosity (penetrates and deep-fills also hairline cracks)
• No need to route out cracks (unlike epoxies)
• Fast-curing (ready in half an hour for overlays or heavy traffic)
• High-strength bond (stronger than concrete)

Applications for CrackWeld concrete repair

Indoor concrete:

• Residential – cracks in basement slabs and foundation slabs on grade
• Industrial – cracks or spalls in factory or warehouse floors subject to heavy traffic – allows heavy traffic to resume in half an hour

Outdoor concrete:

• Driveways – a must before installing overlays to prevent propagation of cracks
• Patios, sidewalks, pool decks – cracks, spalls or “divots”
• Concrete roofs – cracks, spalls, holes
• Bridges, roads, airport runways – cracks, spalls, holes

The repair is rigid. Not suitable for joints that require flexibility like expansion control joints (saw cuts) or floor-to-wall joints of basement floating slabs.

The best first step – RadonSeal concrete sealer

Before repairing cracks, seal the concrete with RadonSeal deep-penetrating concrete sealer. The cracks help the sealer penetrate into the concrete, which preserves and strengthens concrete against further cracking.

RadonSeal concrete sealer penetrates up to 4 inches into concrete, reacts with lime and alkalis, and waterproofs the concrete. It tends to seal fine hairline cracks in slabs. If the crack is also narrow inside, it just might do the crack repair job.

By keeping out water from above or below, RadonSeal protects the concrete against deterioration, pop-outs due to rusting reinforcing steel, spalling or pitting caused by the freeze/thaw cycle, road salts, and chlorine from seawater.

By stopping water seepage and efflorescence (whitish deposits) it will protect concrete overlays, self-levelers, or patches from separating.

About CrackWeld application

The inside of the crack must be clean and dry. The basic steps:

1. Inject the CrackWeld resin into the crack to wet the surfaces and make them tacky.
2. Push dry silica sand into the crack to fill it.
3. Thoroughly saturate the sand with CrackWeld resin to fill it to the surface.
4. In 10 to 15 minutes, scrape off the surface to make it level and use sandpaper for neat appearance.

Hairline cracks which are too narrow for sand are filled and repaired with two passes of the CrackWeld resin.

If additional sand is needed, use a completely DRY graded sand (no fines) or ideally, sandblasting sand with granulation like table sugar (30 to 40 grit) or similar sand without fines.

To repair wide cracks or cracks with a void underneath, first fill the crack partially with sand to prevent the CrackWeld resin from running out.

CrackWeld sets up quickly. Maintain an steady flow of CrackWeld through the mixing nozzle or it may become plugged after a minute or two! After a stoppage, purge the mixer into a disposable cup. To minimize stoppages, repair small sections of the crack at a time say, 5-10 ft. or use up the whole cartridge. Fill the crack with sand in 2 to 3 minutes after priming while CrackWeld is still tacky. On larger jobs, try to get a helper to do the scraping.

Click to enlarge!

Do-It-Yourself CrackWeld Kits

The CrackWeld DIY Concrete Floor Repair Kits are designed for a quick and easy application by homeowners. Each kit includes either two (2-pack) or four (4-pack) two-component CrackWeld cartridges, as well as mixing nozzles, a bag of silica sand, and other accessories.

Coverage:
For full-depth repair of a standard 4” slab, each CrackWeld kit will repair:
        2-pack ... up to 50 ft.of a 1/16” crack or 25 ft. of a 1/4" crack
        4-pack ... up to 100 ft. of a 1/16” crack or 50 ft. of a 1/4" crack

Tools needed – paint scraper or trowel and sand paper (80 grit).

Contents of a 2-pack CrackWeld DIY Kit and instructions on do-it-yourself concrete crack repair

Professional CrackWeld Kits

Click to enlarge!

The CrackWeld PRO Concrete Floor Repair Kits are for contractors or homeowners with many slab cracks. The two-component CrackWeld compound is packaged in dual-tube cartridges. Each kit includes a professional dual-cartridge gun, as well as mixing nozzles, a bag of silica sand, and other accessories.

CrackWeld Concrete Floor Repair Kit contents:

• 2 double-tube sets of RadonSeal CrackWeld resin
• 1 dual-cartridge gun
• 3 mixers
• 3 needles for hairlines
• 3 cross-over restrictors
• 2 retaining nuts
• 1 pair of rubber gloves
• 4 lbs. of silica
• Instructions and MSDS

Video – CrackWeld PRO Kit

The procedure is quick and easy – view the CrackWeld PRO Concrete Floor Repair video!

Coverage: For full-depth repair of a standard 4” slab, each CrackWeld Pro kit will repair up to 100 ft. of a 1/16” crack or 50 ft. of a 1/4" crack.

CrackWeld Concrete Floor Repair Materials (Consumables):
In case additional materials are needed. Same as the Pro kit except for the dual-cartridge gun and gloves.

CrackWeld PRO Kit MSDS

Price and Shipping

Normally shipped the same or next business day. Delivery by courier in 3 to 5 business days. Shipping costs are valid for the lower 48 states. For shipping express, to other states or Canada, please contact us for shipping costs.

ORDER ONLINE

PayPal

Order Form

Any questions? Please contact us by e-mail,
telephone (203) 225-0366 or toll-free 1-800-472-0603

MADE IN USA
Products not sold through retail stores. Available exclusively from:
Radon Mitigation & Concrete Waterproofing Co.
Novion Inc., 18 L'Hermitage Drive, Shelton, CT 06484 USA
RadonSeal™ is a registered trademark. Copyright © 1998-2009. All rights reserved.