Recent Projects - Dunrobin Parging Repair

Dunrobin parging repair 1

We did a parging repair for this customer in Dunrobin. Your foundation supports your home's infrastructure. Maintaining your foundation is necessary to avoid structural issues that can ruin your home over time.

Poured concrete is strong, but even concrete will crack, chip and crumble as Mother Nature slowly has her way. In the picture you can see minor erosion with the exposed foundation where the parging had failed. Cracks, chips, or flaking areas in concrete are not just unappealing; they can lead to further deterioration of the surface and leaks if not properly maintained.

When a foundation is built, a water resistant masonry coating is applied to the outside wall that is called parging. Parging is applied to both poured and block foundations. Repairing your parging will alleviate worsening of your foundation’s condition.

Parging is sometimes confused with stucco but the major difference is that parging is necessary to protect the foundation while stucco is more for decorative purposes. Spring is the best time that the foundation should be checked for damage from the freeze/thaw cycles.

When your basement walls get cracks, so does the parging. This is one reason that parging fails and can cause isolated damp spots in your walls. Another reason is Moisture and the freeze/thaw cycles from our harsh climate in the Ottawa Valley also leads to parging flaking over time.

It is important to remove all the loose parging prior to starting your repair. While the exposed area where the parging has fallen off is evident, there is usually a larger repair necessary than just the area where the parging is missing. Tap around the area with a hammer and if it sounds hollow instead of solid, it is an indication that the parging has separated from the foundation and should be removed and repaired.

Dunrobin parging repair 2

Repairing parging is a lot like plastering drywall with the only caution given is that you have to get it right the first time as you can’t sand it off once it dries.

This is a seven year old home and the parging in this area had previously been repaired and failed. Parging can fail over time and you will see parging repairs that have failed after a short time as the new mortar did not bond well with the old. This repair failed prematurely. We’ll share our best practice which will get parging to adhere to the old cement if done properly. You can find a product called Weldbond http://www.weldbondusa.com/uses.html in many home improvement stores. This is glue which should be mixed at a 5 to 1 ratio with water. Once you have thoroughly cleaned the area to be parged, brush this onto the foundation in the repair area and allow it to dry for one hour. This makes a porous surface sealer which will hold its bond to the new parging. Weldbond should also be added to your cement mix at a ratio of 1 to 1 with your water.

If you have a small area to parge, the premix parging cement is your best way to go.

It is best to parge your foundation under cloudy weather on hot days. As a general rule, you should not parge when temperatures are below 5 degrees Celsius but read the manufacturer’s instructions on the product to be sure. If the temperature is extremely hot, stop and spray a mist on the new parging periodically to prevent the mortar from drying too fast. Your new parging should also be misted with water for a couple of days.

When your cement is mixed and you are ready to parge, spray a mist of water on the area so the wall is damp. This is necessary as mortar forms a bond as moisture inside the blocks is pulled out as the moisture from the mortar is also pulled inward. If there is no moisture in the blocks, all the moisture from the mortar is drawn into the blocks, leaving the parging mortar dry and crumbly before it can fully set.

In the picture below we show our completed job with the parging still wet. While it will dry and the color will be closer to the original parging, it is important to note that the color will not match perfectly when dry and the repair will be noticeable. That being said, it is a very important repair to maintain your foundation.