Use a smooth, even motion, filling the crack flush with the surface, beveling it if it's against the house. You want the rod to fit tight in the joint, so buy it one size larger than the gap. It provides a redundant barrier to weed growth, and most importantly, does not trap dirt and debris like wood and other less flexible products. You could use a flexible adhesive/filler such as SikaFlex Pro, which comes in a “sausage” - but it’s about $20 per unit, plus you need a sausage gun. Let me extend a very warm welcome to the community. Selley’s also make a similar product “Selley’s Flexiseal” -  Polyurethane Sealant, also in a sausage but about $15.00. A word of advice: Keep the urethane caulk off your bare hands and clothes; it’s the stickiest stuff you’ll ever touch. Could we please trouble you for a photo so members can more easily visualise the problem? Then, sweep out and remove any large chunks of concrete and vacuum the area to remove dust and small debris. Resiply makes filling gaps between pavings slabs as easy as 123. Sometimes called as control joints, some contraction joints are already built-in upon ma… Un-compacted fill dirt, erosion, burrowing rodents, decaying organic material even a loss of moisture in the soil can create voids. Use foam backer rod into the gap with your fingers. Or, instead of wood, go to an aluminum carport supplier, and purchase a 1 1/2" x 16' aluminum beam to tap down in there. I found the ground settling under the concrete slab for my paver patio in one corner. New concrete can’t bond properly with the old concrete, so you will have to get something specifically meant for repairs. I removed that because it had become moldy. Underneath was the concrete in the condition you see in these pictures. The backer rod should fill the gap and make contact with the concrete on both sides of the gap. At one glance, they look like lines that divide a slab of concrete into smaller slabs. When you shop for store-bought concrete, you will see a variety of different options. If water seeps between the gap in the asphalt and a house foundation, water can erode the foundation and cause serious structural problems for the house. It is immune to rot, moves with slab expansion and contraction, and is not affected by moisture. Connect a hose to a slabjacking pump, then run the hose to the holes leading to the void. Set the rod 1/4 in. Foam backer rods act to fill in space between concrete joints so you don’t need to use a ton of self-leveling sealant. Fill the crack with urethane caulk, similar to what you would use for driveway caulk. It seems that over the years the ground has settled and the joints between the concrete slabs has become a gap of around 2+ cms  and many CMs deep. The Bunnings Workshop community can help with your home improvement projects. Contraction joints are the deep V-shaped grooves that run across a garage floor. Snip the opening of the tube at a 30-degree angle, making the opening the same size as your gap. Start by taking a hammer and chisel and tapping any rounded edges around the crack or hole to make them straight, which will help the mortar stick better. Step 3 Mix the fill material in a wheelbarrow, using a spade. To remedy this issue I installed backer rod in the gap that I then covered with concrete crack sealant. If … where there is no connection to water on site or there is a hose pipe ban in place. Hope this helps, cheers Deb. We recommend our users to update the browser. As the soil settles or is carried away by other means a gap opens up between the soil and the bottom of the concrete slab resulting in a loss of support. Feel free to post anytime you need a hand or have something to share. The driveway slopes down from my garage to the street. For deeper holes, up to 150mm deep you can use the Deep Fill Repair Mortar. The expansion joint caulk is available at contractor supply stores, well-stocked home centers and hardware stores. Both of these should last a while, but no product like this is going to be permanent. When mixed it is placed in the hole and levelled out. Filling the gap between concrete slabs October 2019 I recently moved into a house with a rather large concreted back yard and want to do something about the weeds that grow between the joints between the slabs. It hasn’t sunk or cracked. Something simple like boiling water might be worth a try.... Workshop is a friendly place to learn, get ideas and find inspiration for your home improvement projects. Follow these instructions and you can do the job yourself. For gaps and joints more than 1/4 in. It seems that over the years the ground has settled and the joints between the concrete slabs has become a gap of around 2+ cms and many CMs deep. Step 1 Mix the contents of both tubs of Resiply together in an empty bucket. If in doubt, call on the services of an expert structural engineer. Smooth the caulk in wide joints with the back of an old … Our latest shed is also a pavilion—and you can build it, too! Caulk cracks 1/4 in. This will ensure a water tight seal. Water can get into the joints, freeze and then expand, making the cracks even larger. Expansion and contraction joints are not just products of sloppy construction work or mistakes in measurements. Fill the gap with polymeric sand or caulk. That's when cracks appear in the concrete slabs. Use a dry mix of 1 part cement to 6 parts dry sharp sand. The gap in question was previously filled with either fiberboard or concrete crack sealant, but enough of it has deteriorated to conceivably allow moisture in. After a while, the expansion joint can dry out and won't absorb the stress as well as it once did. Fill the gaps you see in the photos. A slabjacking pump is specifically made to pump the fill material beneath concrete slabs and can deliver the material quickly. If the slabs are bedded on concrete or cement-based mortar, you’ll have more of a chance with pointing or grouting. Wear disposable gloves when you’re tooling the joints. Complete DIY projects like a pro! Let me know if you need a hand with uploading a photo or getting the most from the Workshop site in any other way. These gaps are really meant to be there for substantial reasons. Following on from @Mathy's point about weed control, you might be interested in the tips on these previous discussions. DEAR TIM: My concrete driveway has eight large slabs. First make sure all the gaps are clean and free from loose debris, jet washing paving slabs is a great way to quickly prepare your paving for jointing and grouting. There’s a wide ugly gap between my concrete outdoor patio slab and the slab my house is built on. You could contemplate some sort of grout, which would be a hard filler, so will crack and fail eventually. Planning concrete expansion joints correctly is a complicated business and one that should be given careful consideration. Gaps against a house can direct water against the foundation, leading to more problems. Good for installations where there is limited water, e.g. Can anybody advise what is the best way fill in these gaps and thereby prevent weeds? Fill holes with a mortar mix instead of regular concrete. Use a smooth, even motion, filling the crack flush with the surface, beveling it if it's against the house. It works perfectly as a concrete expansion joint sealant. Fill the trenches on either side of the driveway with small, rounded pea gravel (the size of marbles or peas). Smooth the caulk in wide joints with the back of an old spoon. Brush all of it off the slabs to avoid staining them. We are no longer supporting IE (Internet Explorer) as we strive to provide site experiences for browsers that support new web standards and security practices. I have a concrete front entryway which up until a few months ago was covered by gray "Astroturf". Alternatively, I got rid of my recurring weeds in my pavers in 2 years by applying Roundup - so, a bit of work for a couple of years, but this year - no weeds. It works perfectly as a concrete expansion joint sealant. Brush across the whole area using a softer brush, filling all slab gaps evenly; Compact the mix into the gaps with a trowel; Repeat as above until all gaps filled and mix brushed off slabs; Spray area with a light mist from the hose to dampen the mix, activate cement. Push the backer rod down into the joint with your hand. Snip the opening of the tube at a 30-degree angle, making the opening the same size as your gap. Re: Filling the gap between concrete slabs, Top 10 most popular outdoor furniture projects. Gaps can occur between asphalt and concrete for many reasons, including weather changes, vehicle-inflicted damage or improper installation of the asphalt. The original filler material is a tar sheet material which has degraded and is practically non-existent in some joints. Cracks and gaps in concrete are more than just an eyesore. You can also repair mortar joints yourself. The straight-line gaps between the slabs has … This one is probably the biggest of the lot. Alternatively, the gap appears wide enough that you could pour a sloped concrete border. Filling Deep Holes in Concrete Paths, Slabs, Drives and Hard Standings. Pros and … This material acts as a shock absorber, absorbing the stress from the slab's movement. Personally, I would cut out a few feet of concrete, and pour a 2' or 3' strip in there. Hi @BloodyIrishman (great name btw) - what you do depends on how many gaps there are to fill, and how much time/money you want to spend. I would like to do the following by myself if I can because I am currently unemployed: 1. When this occurs, it's time to replace the expansion joints. 4. Use a brush to brush it into the gaps between the slabs. No Shortage of Gaps Permalink. lower than the surface of the concrete. This epoxy mortar has quite large (up to 4mm) aggregate within the resin and, as usual is mixed with a hardener. wide, install foam backer rod to support the caulk. Most home improvement stores sell these products and you can apply them right over your gap or crack. It creates the appearance of a sand filled joint but it is in fact a rigid bound compound creating a strong bond between the blocks / slabs / setts / flags. Once there, voids are difficult to fill. We trust that you'll receive loads of helpful information, advice and inspiration for your projects around the house and garden from our clever and creative members. Use the end of a putty knife to push the rod firmly into the gap. Wipe the spoon clean as needed with a rag and mineral spirits. I recently moved into a house with a rather large concreted back yard and want to do something about the weeds that grow between the joints between the slabs. What is the best way to fill the gap … Moisten (but do not drench) the problem area, then apply the mortar mix with either a mason’s trowel or a putty knife. Draw the gun down the crack, smoothing the caulk with the tip as you go. Sign up for our newsletter! Here's how. If you get some on your skin, quickly wipe it off with a paint thinner–dampened cloth. Be sure to physically separate this from the house and the existing slab and strike control joint in the border every so many feet. You can repair a concrete floor by cleaning and straightening the damaged area, and then filling it with mortar. Fill the crack with urethane caulk, similar to what you would use for driveway caulk. Stuff the rod into the gap, filling it up to about 1/4-inch from the surface of the concrete. Auto-suggest helps you quickly narrow down your search results by suggesting possible matches as you type. Here’s a BIG TIP: the diameter of the backer rod should be 1/8 inch larger than the width of your concrete expansion joint. Fill the crack up to the surrounding concrete surface. Creating the right gaps, at the right spacing and filling them with the correct material is vital to protect the integrity of the concrete slab. Next, check out an amazing brick project you can DIY to make your backyard so much better. I have seen this done using an icing piping bag arrangement (I kid you not!) Brush the surface of the patching compound with a dry paintbrush to texture the surface, if desired. wide or less without using backer rod. 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