How to screed an internal floor?

June 15, 2006 6:09 AM

How do you screed an internal floor with a dry concrete mix?

A friend has had the copper pipes under his house replaced. As a consequence, the existing screeding was channelled out (approximately a 12 inch channel). He is looking into re-screeding the channel himself. Does anyone have any recommendations about good ways of going about this?

posted by plep to Home & Garden (7 answers total)

Just use some self leveling concrete, should work a treat on a 12" channel.
posted by zeoslap at 6:21 AM on June 15, 2006

What zeoslap said. Here's a link.
posted by Floydd at 6:31 AM on June 15, 2006

How large of an area needs to replaced? If it is large enough then he may want to order a small load of concrete and bring it in by the bucketload. Otherwise mix the concrete in as large a batch as you need in the basement with portland cement, sand, and water. All he will need is a good magnesium float. It doesn't take much to create a flowline with a float if that is what you are after, especially in an area the width of a foot.
posted by JJ86 at 6:43 AM on June 15, 2006

I don't think an epoxy floor topping is going to help you if I understand your situation correctly.
posted by JJ86 at 6:44 AM on June 15, 2006

What JJ86 said! a good idea as well is to drill holes in the side of the channel (both sides) and install short bits of rebar or even old bolts. This will make the entire pour adhere to the existing slab and prevent it from dropping later.You can also use fibre crete ,cement in a bag impregnated with glass fibres to increase strength and nix the bars.Fibre crete is about 3 times the cost of standard concrete though.Make sure you wet the edges of the existing pad before pouring cement.
posted by plumberonkarst at 8:35 AM on June 15, 2006

Adding to my previous post.Make sure you cover the copper pipes with a barrier.Plastic is easy enough but I always found using spray undercoating for car rocker panels worked well and was exceedingly quick.Technically this should not be a problem (old concrete had a high ash /slag content so corrosion was prevalent) newer concrete "shouldn't" cause corrosion but we always felt it prudent.Certainly this is a lot easier than breaking concrete to repair corroded pipes.A better product for piping in a concrete slab is


http://www.toolbase.org/techinv/techDetails.aspx?technologyID=146


" Pex pipe " is continuous with no joints and integral corrosion resistance.There are many adapters to various piping materials.
posted by plumberonkarst at 8:47 AM on June 15, 2006

I've worked with the various SikaTop concrete repair materials and they seem to work pretty well. Choose one that suits your particular needs.

Also, your basement slab is likely unreinforced, so doweling in rebar is probably not necessary, but you do want to make sure the bottom of the repair patch is slightly larger than the top so the patch is keyed in. Also make sure the area to be patched is clean and damp before pouring. You could also go at the patch with a wire wheel prior to cleaning just to open up the surface and help the patch material bond.
posted by electroboy at 1:43 PM on June 15, 2006