DIY: Painting Your Foundation Refreshes Your Home’s Exterior

Most homeowners remember to maintain their home’s exterior cladding and repaint it regularly. The foundation, however, is easily overshadowed by the cladding and eventually starts to deteriorate. If you recognize your own foundation in this description, now is the time to give your foundation the attention it deserves and restore it to good condition.

When is foundation painting necessary?

Foundations are typically constructed either by pouring concrete or by building with blocks, most commonly lightweight aggregate blocks. A block foundation is often leveled with mortar to achieve a smooth finish.

To complete the appearance, the foundation may be coated with a textured finish or painted.

Water can penetrate through damaged coating into the leveling mortar and gradually deteriorate it until the mortar eventually separates from the foundation surface.

The coating phase is primarily an aesthetic consideration and has a surprisingly significant impact on the overall appearance of the house. At the same time, the coating also protects the foundation from external moisture. For example, during rain, the eaves do not protect the house all the way down if there is any wind. Similarly, rainwater hitting the ground can splash onto the foundation.

Water can penetrate through damaged coating into the leveling mortar and gradually deteriorate it until the mortar eventually separates from the foundation surface.

Of the coating options, painting is both the most affordable and easiest option, and it can be successfully done by a homeowner as well. Here are some tips on how to do it.

Check the foundation’s condition before painting

When maintaining the foundation, it’s good to ensure at the same time that the foundation is structurally and moisture-technically sound. Things to check include ensuring the foundation is straight and has no cracks, that drainage systems are functioning properly, and that ground slopes and rainwater direct away from the house.

By tapping with a hammer, you can hear from the sound how large an area the rendering has separated from.

In a rendered foundation, it’s also good to watch for possible cracks. They are unwelcome signs and indicate that the rendering around the crack has separated from its base.

By tapping with a hammer, you can hear from the sound how large an area the rendering has separated from. Water can penetrate through the crack behind the rendering and deteriorate the rendering further.

If problems are found, it’s important to fix them before improving the foundation’s appearance. If you don’t do this but proceed directly to the painting phase, a false impression of the foundation’s condition may be created.

Choosing foundation paint

Foundation paints are available from several manufacturers. The most familiar to consumers are likely Tikkurila’s Yki and Teknos’s Saku foundation paints.

However, these two are not automatically suitable for all foundations—when choosing paint, you need to know the foundation’s construction material. It’s especially important to know whether lime has been used in the concrete foundation’s casting mixture or in the block foundation’s leveling mortar.

If there have been adhesion problems with previous paint, the old paint should be completely removed before repainting and the suitability of the new paint type for the surface should be confirmed.

Lime is the main cause of paint detachment, especially in concrete foundations, so its possible presence should be investigated. If lime has been used, it’s best to choose an inorganic paint like Tikkurila’s Kivitex, which breathes well and allows lime seeping from the foundation to pass through without detaching from the surface itself.

If the foundation has been painted before, the chosen paint must be compatible with the previous paint. If there have been adhesion problems with previous paint, the old paint should be completely removed before repainting and the suitability of the new paint type for the surface should be confirmed.

Planning the painting work

In all painting and especially in exterior painting, it’s extremely important to plan the work well and prepare the surfaces to be painted before picking up the brush.

If you want a particularly neat result, start by removing a few centimeters of soil from around the foundation. This makes working easier and keeps the paint edge below ground level even when the ground level settles slightly over the years.

Protecting is considerably less work than cleaning paint splatters from places where they don’t belong.

Next, protect any windows and doors in the foundation and all other surfaces that are not meant to be treated. Protecting is considerably less work than cleaning paint splatters from places where they don’t belong.

Work preparation also includes considering suitable painting weather and planning the work sequence. The best painting weather for foundation painting is overcast.

The temperature must be at least +5°C and the relative humidity below 80%. Painting in direct sunlight should be avoided to prevent a blotchy paint finish.

Preparation is the number one priority in foundation painting

To ensure the most durable paint surface possible, the foundation must be thoroughly cleaned before painting. A paint surface applied to a dirty base can quickly start flaking and cause unnecessary work when the foundation has to be repainted prematurely.

Washing can be done either with a pressure washer or a brush. If mold or moss is visible on the foundation, use a mold remover to help with washing. It’s important to completely remove mold, as mold will continue living under the paint surface and later cause the paint to detach from the foundation.

If there are significant holes in the foundation, they can be patched with suitable leveling mortar before painting.

New, previously unpainted concrete foundations may have cement paste on the surface that won’t come off with just water washing but requires, for example, grinding with a grinding stone.

After washing, remove all flaking and poorly adhered paint, for example by wire brushing. If there are significant holes in the foundation, they can be patched with suitable leveling mortar before painting.

How to paint the foundation – instructions

If the foundation is being painted for the first time, it’s recommended to prime the entire foundation. If the foundation has been painted before, it’s sufficient to prime only the parts where the old paint has come off.

Primer helps achieve an even result, extends the durability of the paint surface, and prevents possible salt problems from emerging.

However, it should be noted that painting cannot fix severe salt problems—their cause must always be investigated and fixed before painting the foundation. Primer should always be chosen to be compatible with the topcoat.

Once the primer has dried, you can move on to the topcoat phase. Usually one coat of paint is sufficient, but if you want to change the color or are painting the foundation for the first time, it’s good to apply two coats.

When painting the foundation, be especially careful with small pores and holes, which are often present in cast concrete surfaces.

The first coat is applied with slightly thinned paint and the second coat with undiluted paint. A roller or brush works as a painting tool according to your preference.

When painting the foundation, be especially careful with small pores and holes, which are often present in cast concrete surfaces. They are easily missed when the paint forms a film over the hole. However, when drying, the paint film pops open and the stone surface becomes visible.

The work sequence should be planned so that you paint one entire side before taking a break. This ensures a uniform paint finish for each side.

Hesitant to pick up the brush?

With good preparation and the right products, painting the foundation is surprisingly quick and easy and will certainly succeed even for a less experienced painter.

If you’re still hesitant about undertaking the work, you can always call in a professional. From Väriset, foundation painting can be ordered in connection with exterior cladding painting, and you’ll also get the same reliable warranty for the foundation as for other painting work.