How to Repair and Seal Non-structural Foundation Cracks

Many building foundations develop non-structural cracks, often caused when the building settles into the ground below and around it. Usually, these cracks do not pose any threat that the building will collapse, but they sometimes allow the outside elements to infiltrate to the inside, resulting in added energy costs to mitigate cold, hot or humid air or moisture and dampness.

Instructions

Difficulty: Moderate

Things You’ll Need:

• As noted in text.

1. Analysis of foundation cracks:
   First of all, this article does not teach you how to know whether or not a foundation crack is structural in nature. In order to determine that, you might need to hire a structural professional.
   
   This article only discusses a means to seal non-structural foundation cracks, in an attempt to minimize outside element infiltration to the inside of your home.
   
   Note that the following steps should be done on the inside and the outside of the foundation, where accessible.
2. Once you have determined that your foundation cracks are not structural in nature, follow these steps to make repairs and seal them.
3. Procure products, tools, and equipment:
   You will need the following items to repair and seal non-structural foundation cracks. Most items are available at home centers and hardware stores.
   
   o Hydraulic cement -- needed if cracks are wide, and/or if water is leaking through. Note: if water is leaking in, you probably should call that structural professional, just to be sure the water pressure outside is not applying dangerous exertion against the foundation.
   
   o Caulking -- look for special caulking intended for concrete repairs.
   o Foam backer-rod -- if cracks are fairly deep, backer-rod helps fill it prior to caulking.
   o Caulking gun -- get one that is durable and strong.
   o Small and large putty knives
   o Cold chisel
   o Hammer
   o Wire brush
   o Protective clothing, gear etc., as recommended by manufacturers of tools, products and equipment.
4. Start by cleaning out the non-structural cracks using a hammer and a cold chisel.
   
   You will want to remove any crumbling, soft or loose pieces of the foundation material, especially near the edges of the cracks.
   
   Then, clean out the cracks with a wire brush. You can use either a hand held wire brush, or perhaps a rotary wire brush in a drill motor.
5. If the non-structural cracks are not too wide or too deep, you will be able to re-seal them using only the concrete-repair caulking.
   
   If the cracks are deep, press some foam backer-rod into them to fill some of the void. You don't want the caulking material to end up too thick; perhaps 1/2 inch at most; review manufacturer's guidelines for best practices.
6. Once you have the cracks cleaned and prepped, you are ready to apply your caulking. Start at the top of the crack, and gently but steadily squeeze it into the crack, filling the void so the caulking protrudes slightly beyond the edges of the crack.
   
   Once you fill the entire length from top to bottom, use a wide putty knife that spans the width of the crack to smooth out the caulking so it is relatively flush with the surrounding surface. Press firmly and add caulking as necessary, so caulking fills in voids in the crack.
7. Once the caulking has dried, you can paint it; check manufacturer's instructions for specifics. For best results, use a waterproofing sealer-paint designed for your foundation material.
8. If your non-structural cracks are significantly wide, or especially if water is seeping through and you know the outside ground-water pressure is not creating undue exertion against the foundation; because you had the pro's review it for you; you can fill and seal it using hydraulic cement.
9. Hydraulic cement is designed to expand as it cures, which helps to fill and seal larger voids and cracks, and is especially useful where water seepage is evident.
   
   Usually hydraulic cement comes in power form, although it might be available ready-mixed as well.
10. Of course, you must still clean out the cracks as described above. Once that is done, you can mix and apply the hydraulic cement.
    
    Using a smaller putty knife at first, fill in the crack with cement until it is protruding slightly beyond the surrounding surface.
    
    Then, using the wider putty knife and spanning the width of the gap, smooth out the hydraulic cement so it is flush with the surrounding area.
    
    Allow the hydraulic cement to dry thoroughly before painting. Use waterproofing sealer-paint designed for use on your foundation material.
    
    Visit the link below for "More Ways To Save Energy At Home", for additional tips.

Tips & Warnings

• Keep a bucket of water handy, to dip your putty knives and other tools. This helps prevent the caulking and hydraulic cement materials from sticking to the tools.
• Read and follow all manufacturers' guidelines and instructions for safe use and handling of tools, equipment and products.
• Wear adequate protective clothing, gear and equipment as recommended by manufacturers.
• Clean up as recommended by product manufacturers.