A bare concrete porch base
The before photo shows the porch foundation as plain light grey concrete, with a rough, uneven face and a raw lip under the porch deck. The porch stairs and white railing were already in good shape. Against them and the light grey siding, the bare base looked unfinished.
Exposed concrete also takes the worst of the weather. Water soaks into the surface, freezes and flakes off the face over a few winters.
Frost does the most harm right at grade, where snow melts against the concrete during the day and refreezes overnight.
Patching and parging
Parging is a thin cement-based coat troweled over a concrete or block foundation. It smooths the surface, hides patches and gives the wall a protective skin.
The crew cleaned the concrete, filled the cracks and prepared the surface so the new coat would bond. Then we applied a smooth parge coat with a fine texture in charcoal grey, running from the porch cap down to the soil line.
The same charcoal coat continues along the house foundation beside the porch, so the base of the front elevation reads as one band under the siding. The white columns and railing stand out above it.
A good parge coat bonds to the concrete behind it. If it goes onto dust, loose flakes or old paint, it lets go in the first hard winter. Surface prep takes longer than the coat itself.
Vents and clean edges
Small round white vents set into the parged skirt let air move under the porch. Airflow keeps moisture from building up under the deck, which protects both the framing and the new finish.
We finished the top edge crisp under the porch deck and worked the coat tight around the black standpipe and the downspout. Clean edges are what make parging look intentional instead of patched.
Keeping a parged foundation looking good
Keep downspouts running away from the foundation and garden soil sloped away from the wall. Parging lasts longest when water does not sit against it.
Small hairline cracks can appear as concrete moves with the seasons. Catching them early with a touch-up keeps water from getting behind the coat.
If you are planning parging on your own home, look at the foundation around the whole house as well as the porch. Matching the porch and the foundation in one pass gives you one colour and one texture all the way around.
