How to Fasten a Trim Board to Concrete

A window without a trim board is a window that has no character. This is especially the case if the window is in a basement. Many homeowners will not bother adding trim boards to their homes when the window is set in concrete. This is because concrete is incredibly hard and nailing anything to it in the traditional sense will prove ineffective. The following article will show you how to install a trim board to the concrete surrounding your windows.

Step 1 - Guide Lines

To properly attach trim board you need to know where it'll go and that it's level. Making sure these are accurate will save you time in the long run. Hold one piece of the trim board up to the window. Make sure it is flush with the edge where the window meets the concrete. Use your level to make sure it's perfectly straight. When you are certain of these two things, draw a line along the outside of the trim board. Repeat this with each piece of trim board.

Step 2 - Pilot Holes

Just grabbing a nail and hammering the trim board into the concrete will most likely cause the concrete to crack and crumble. When this happens you lose structural integrity of the window. If this happens you open yourself up for other issues down the line such as water entering the home as well as a loss of heat. Select a concrete drill bit that is a fraction smaller than the concrete fastener. Measure 1/2-inch in from the edge of the window and make a mark every 6 inches.

Drill a hole slightly shorter than the length of the fastener. Repeat this for each side of the window. Measure these same distances onto each piece of trim board and drill each of them out as well with a bit that has a diameter smaller than the nail. When you are making these holes it is important to use sizes smaller than the next piece of material to be added. This is both the length and the diameter.

Step 3 - Fasten the Trim Board

Fill the holes with the epoxy adhesive until they are about 1/2 full. Work with one side at a time as the epoxy adhesive can cure quickly making it difficult if not impossible to properly sink the nails. Place the first section of wood trim against the wall and line it up with the guideline you made. Take one of the concrete fasteners and insert it through the pilot hole in the trim and make sure it sets into the concrete pilot hole.

Tap it in with the mallet so you do not damage the wood trim or the concrete. Use a screwdriver and insert it into the fasteners and turn it to embed the fasteners. Insert the nails and hammer them in place. Insert the top and bottom nails first then fill in the remaining nails. Repeat this step until all of the boards have been installed.