Painting and Weathering Concrete

Apply grey primer first, then a base coat of concrete grey.

Aged Concrete​ - Behr Formula

Aged Concrete​ - Glidden Formula

Behr Color Samples FLAT

Ultra Lt. Grey - Behr Formula

The above paints are Behr FLAT Color Samples from Home Depot – about $3.50. To print or save these photos – right mouse click on them and choose view image or save image. Bring these photos to the paint dept. and they should be able to mix them for you. If they don’t have Behr try the Glidden formula for the same color.

These FLAT water based colors can be used to mix various shades of concrete grey from new to aged. Start with Light Grey and add the Aged Concrete color in little by little.

Apply several coats in thin washes. Experiment with washes of different shades on top of each other. See the field photos below for reference.

Another paint that makes a good “New Concrete” color is Rustoleum CHALKED Aged Grey. This can came from Walmart. Dries FLAT. Use this as a base color before weathering.


Its important to have a photo as reference when weathering. Concrete objects may look wildly different depending on the climate they are in so its important to obtain a photo of an object in the climate you are modeling. In dry areas you will see different shades of grey and discoloration from decades of accumulated dust from the surrounding soil. You may see black soot from diesel exhaust and long gone steam engines. In wet climates you may see dark colored molds, greens and yellows from moss and other biofilm as well as many shades of grey. If the object is in water there will be high water marks and other marks made by water.

You will also notice in some spots the concrete is chipped, cracked, crumbling and patched. The above photos of Tunnels 3 (the opening), 16 (wing)  and 17 (header) show various patterns of missing concrete where it has fallen away.

3D printed resin parts lend themselves nicely to simulated chipping. Edges and faces may be scraped, filed, sanded or struck with a hard, sharp metal tool to simulate crumbled concrete. Use a light force when striking. Be sure to wear eye protection when chipping resin. Resin can also be nipped with wire cutters. The chips may be sanded smooth for older chips  or left with sharp edges for more recent chips. For the bravehearted extreme weathering fanatics, break the part completely in two, chip away at the crack and then super glue back together making sure not to let glue ooze out to the front. (Voids warranty).

Paint the portal with a new concrete color of light grey. Use varying shades of the grey laid down in thin washes or dry brushed. Add soot by dry brushing. A light wash of black will highlight form lines and simulate soot. To simulate patched areas, trowel on putty, Spackle or joint compound.

After the portal has been chipped, painted, black washed, soot added and installed, dry brush a thin wash of the color you painted on the surrounding dirt to simulate dust. Take your time and do thin layers. Add weathering powders and chalks. Apply graffiti if desired. Dry brush your concrete grey and dust color lightly over the graffiti to make it look faded.

New chips will be more grey  where the new concrete color has been exposed. Older chips will be closer to the color of the dust.