Fresh concrete changes for weeks after the pour, and some of what worries owners is normal. Some of it is not. This page sorts the two, with the cold-climate causes we see around Anchorage.
Why is my new concrete already cracking?
New concrete cracks because it shrinks as it dries. Hairline cracks in the first weeks are common and mostly cosmetic. Wind and low humidity, both common on a clear Anchorage day, dry the surface fast and cause fine surface cracks if the slab is not cured. Wider cracks, or cracks away from the joints, point to joints cut too late or a poor base.
Is the contractor responsible for a crack that shows up weeks later?
The contractor is responsible when the crack comes from the work: no joints, joints cut late, a thin slab, a base that was not compacted or concrete placed on frozen ground. Hairline shrinkage cracks are generally treated as normal in the trade. Read what your contract says about cracks, take dated photos and raise it in writing.
Why does my new concrete have dark and light patches?
Dark and light patches come from uneven drying. Shaded and damp areas stay darker for longer, and a slab covered with blankets or plastic for cold weather often shows marks where the cover touched it. Most of this evens out over a few months. Blotches that remain usually trace to different truckloads, water added on site or uneven finishing.
What happens if it rains on fresh concrete?
If it rains on fresh concrete in the first few hours, the water can wash cement off the top and leave a weak, sandy surface. Once the slab has been finished and has set, rain does no harm and helps curing. Late summer in Anchorage is the wet season, so a crew should have plastic on hand. If your slab was rained on, check it after a month for dusting or soft spots.
There are footprints, rough spots and low spots in the finish. Is that acceptable?
No. Footprints, trowel marks and low spots that hold water are workmanship faults. Birdbaths matter more here than elsewhere, because standing water becomes a patch of ice. Minor marks can be ground out. Low spots can be filled with a bonded topping, though the patch will show. Photograph the puddles after rain so the size is clear.
Are control joints really necessary? The contractor says he will saw-cut them a week later.
Yes, control joints are necessary, and a week later is too late. A slab begins to shrink within hours and will crack where it wants if there is no joint to guide it. Joints should be tooled in during finishing or saw-cut as soon as the slab can take the saw, normally the same day or the next morning. In cool weather that window is a little longer, but it is not a week.
I found out my slab was poured without rebar or mesh. What now?
A slab poured without rebar or mesh is not automatically bad. Steel does not stop cracks. It holds them tight and keeps the pieces level. A patio on a good gravel base can do fine without it. A driveway on frost-prone ground is more likely to end up with stepped cracks. If the contract listed steel and none went in, you did not get what you paid for, and that should be put to the contractor in writing.
My new stamped concrete is slippery, or the sealer is cloudy, fading or peeling. Why?
Slippery stamped concrete is a sealer problem. A glossy film sealer on a smooth pattern has little grip when wet and none under frost. The fix is to recoat with a grip additive mixed in, or to strip the gloss and use a penetrating sealer. Do this before winter.
A cloudy or peeling sealer has moisture trapped under it. That happens when sealer is applied too thick, on a damp slab, or in cold weather, all of which are easy mistakes in a short Alaska season. The usual cure is to strip it and reseal thinly on a warm, dry day. Fading is wear, and a fresh coat brings the color back.
The surface flaked in its first winter. Is that normal?
No, flaking in the first winter is not normal. It points to concrete without enough entrained air, a surface overworked with water, a slab that froze too young, or deicer used in the first season. The mix ticket from the supplier shows the air content that was ordered. Ask for a copy. That piece of paper often settles the argument.
It was poured in unusual heat and now looks bad. Was that a mistake?
Extreme heat is rare in Anchorage, but a slab poured in hot sun and wind on a 75 or 80 degree day can still dry too fast. The signs are fine surface cracks, a rough finish and weak edges. The crew should have dampened the base, worked quickly and cured the slab right away. If they did not, the surface may wear early.
The stamped pattern is crooked and I have not made the final payment. What should I do?
Hold the final payment until you have an agreed fix in writing. Photograph the pattern lines against a straight edge. Small misalignments can be touched up with stain and hand tools. A pattern that is plainly off across the slab cannot be re-stamped, so the choices are a price reduction, an overlay or a redo. Keep talking, and keep it in writing.
The crew left ruts in the lawn, washout and splatter. Who fixes it?
The contractor fixes it. Ruts from trucks, a pile of washout and splatter on siding are part of the job to clean up, unless your contract says otherwise. Ground is soft in spring here and ruts are common, so agree on the truck route before the pour. Send photos and ask for a date for the repair.
My new pad is out of level, or the forms were left on and are stuck. Is that a defect?
It depends on what you asked for. Outdoor slabs are meant to slope a little so water runs off. A pad for a hot tub, a shed or a generator should be level or very close. If it is out of level against what was agreed, or water runs toward the building, it is a defect and the contractor should correct it.
Forms left on are a related complaint. Forms normally come off in a day or two. Left for weeks, the wood swells and grips the concrete, and pulling it can chip the edge. Wood left in the ground also holds water against the slab. Ask the contractor to remove the forms and patch any chips. It is a small item but it belongs on the list.
What can I do if the contractor will not come back to fix it?
If the contractor will not come back, write down the problem with photos and dates and send a written request with a deadline. Alaska contractors are registered with the Division of Corporations, Business and Professional Licensing and must post a bond, so you can file a complaint with that office and ask about a claim against the bond. The Alaska Attorney General's Consumer Protection Unit also takes complaints. Small claims court is another route for smaller amounts.
The only real price is one written after we have seen the site. Call (907) 331-4363 or text us a photo of the area to set up a free on-site estimate.