No wall crack is the same. They can vary in length, width and direction. Typically, larger cracks (those bigger than 15mm in width) are a cause for concern, as they could point to structural issues. You'll want to get these inspected by a structural engineer.
Cracks of less than 5 millimetres wide are usually a crack in the plaster, rather than the wall itself, and can be filled and decorated over. Cracks between 5mm and 15mm wide are more likely to be serious and may need professional repairs. Any crack bigger than 25mm wide should definitely be examined by a professional.
Here's how to know if a crack is structural: One of the easiest 'tells' for structural damage cracks is that they grow over time. A thin, non-structural crack can quickly become a structural foundation crack if it gets wider after several weeks or months.
Filling Cracks
On interior wall surfaces like drywall and plaster, the material that gives the most inconspicuous repair is joint compound. Joint compound comes in pre-mixed "mud", as it is referred to, that comes in 1 gallon and 5 gallon buckets.
If you have to paint a wall presenting a crack, a solution would be to apply an elastic and over-paintable material inside the crack. Then, apply the paint. Since paints are very thin layers, the material will follow the movements of the crack and will not highlight the problem.
However, a plaster filler like Polyfilla or a powder filler are probably the best options for filling plaster cracks, as alternatives such as caulk are best used for other purposes, like sealing gaps around pipes or tiles.
Hairline cracks under 1/2 inch long can often be patched with a thin layer of drywall spackling compound. Use a small putty knife to spread the compound evenly over the crack until it's flush with the surrounding wall.
Erase-A-Hole The Original Drywall Repair Putty
It's a soft putty that comes in a compact applicator to quickly work the product into small holes and cracks. It works great on drywall, plaster, and wood—though we wouldn't suggest using it on anything bigger than a . 5-inch hole.
You can also use acrylic nail polish to hold the glass together temporarily. This has proven to be quite successful in preventing cracks from spreading, especially when you have nothing else at your disposal. You can also apply clear masking tape over the dirt-free crack to prevent further dirt from entering the crack.
Crack sealing is a more costly procedure for the pavement owner but provides substantial value due to its long life expectancy. While crack filling may only last one or two seasons depending on the cracks activity, crack sealing can last up to 8 years or more and is considered a permanent treatment.
Add Jointing Tape
The jointing tape should be completely embedded in the filler. Also, make sure there are no bumps or wrinkles in the tape. The jointing tape bridges the crack and tolerates slight movement which is why the tape will ensure that the crack won't return.
If cracks rapidly get bigger in length, wider, or change in any way, they may present serious issues. It's best to hire a structural engineer to inspect them.
The fillers are generally used to fill gaps and holes in walls and wood (often decayed wood). Putty is used to smooth relatively small uneven surfaces caused by screw holes, scratches or coarse materials. The DIY tasks can be very specific.
Toupret Fibacryl is a specialist flexible filler, which is suitable for filling and repairing movement cracks, problem cracks, and moving cracks on internal and external projects.
Polycell Crack Free Ceilings is a great way to restore cracked ceilings to a smooth 'good as new' finish. It's flexible paint formulation uses Polyfilla technology to not only cover cracks but prevent them from reappearing.
A small crack in your wall doesn't necessarily mean you have a serious foundation problem on your hands. Minor cracks that are only surface level are often harmless and can be patched with a little drywall putty and a new coat of paint.
Stair-step cracks along mortar joints or through the actual brick are almost always a serious matter—especially if the wall is bulging or if the cracks are larger than ¼ an inch. If you notice stair-step cracks in your foundation walls, call a contractor at USS immediately for a free foundation estimate.
Detecting Crack Depth
Accurate depth measurements require instruments that look for discontinuities in the concrete to indicate the extent of a crack. Ultrasonic pulse velocity is one such method and operates by detecting the travel time of stress waves of ultrasonic energy transmitted through concrete sections.