How to Lay a Concrete Basement Floor Part 1

As any general contractor knows, a concrete basement floor must be level and it must be poured in sections to prevent cracking. If you are building a new house and plan to pour your first basement, you will need a good set of instructions such as those below.

Step 1 – Place Plumbing Stubs

Before pouring concrete it will be important for you to lay plumbing stubs that can be used in the future for sewer drainage. Be sure to cover their openings. This will help to keep debris out of them.

Step 2 – Cover Your Dirt Floor with Sand

Cover our dirt floor with 3 inches or more of sand. This is the best insurance you can use to give your concrete floor a base that is compact and less likely to crack.

Step 2 – Install Rebar

Reinforce your concrete by placing rebar and rebar chairs. Space bars at least 2 feet apart, and place chairs beneath them where the bars intersect. This will place your rebar in the center of the pour where it will give you the greatest reinforcement.

Step 3 -  Mark Your Proposed Floor Surface

For greater assurance that your basement floors will be level, once they are poured and smoothed, place a mark on the wall that will indicate where the poured top surface should be. There are 2 ways you can accurately determine these level marks. The first way, if top surface of your basement walls are level, is to measure down from the top to a point 3 1/2-inches above your compacted sand. This is where you mark should make your mark on the wall. The second and most accurate way is to use a laser level.

Step 4 – Install a Screed Guide

To give yourself an accurate and level guide to use when you screed your freshly poured concrete, make a screed guide. Use a piece of 2x4 lumber, about the same width as the wall where you'll be pouring your concrete. To mark where the top edge of this guide should be, place a mark 5 1/2-inches above the floor surface mark you make earlier. Use concrete nails to fasten this board to the wall with its top edge at the mark you just made.

Step 5 – Make a Screed

Make your screed from a 2x6 board that is about 12 inches longer than your poured floor's width. To the middle of this screed you've just made, attach the screed vibrator, then run its cord to the open side of your pour.

Step 6 –Make a Screed Cleat

Make a cleat from a 1x2 board, 2 feet long. Fasten it to the screed top, leaving an overhang of 2 inches. You'll use this cleat to level the concrete.

Step 7 – Set up a Second Screed Support

Create a second support for your screed at the far side of the screed, the top of which will be the same level as your poured floor surface. When finished, you are now ready to pour your concrete.