How to Paint a Basement or Cellar

Updated May 16, 2024 | Posted Nov 15, 2023 | Professional insight, Product Advice | 0 comments

In this blog I’m going to explain everything you need to know about how to paint a basement; from preparation to finish. Follow this advice and your basement will look good for years. Cellars are painted in exactly the same way.

Painting a basement comes with its own set of challenges. Because they are under the ground, unless they’re tanked, the walls usually contain a certain amount of moisture. Basements sometimes have problems with mould, and they’re often very dusty.

The paint you use needs to be capable of withstanding these conditions. It isn’t just about choosing a good colour, but you need the paint to be waterproof enough to keep moisture out. Plus, it needs to stop future mould growth. You also need to carry out your preparation work to a proper standard, otherwise no paint system has a chance.

 

Shopping List

  • Cleaning agent
  • Mould treatment
  • Specialist paint
  • PPE – Gloves, mask, etc.
  • Long-pile paint roller
  • Synthetic paint brush

 

How to Paint a Basement or Cellar

 

I’ll start by quickly running through the steps you need to take. I’ll then go into more detail further down the blog and recommend the products I think you should use.

 

Step 1 – Clean Every Surface

Loose material, dust, and all contaminants need to be removed before you can start painting.

 

Step 3 – Treat Mould

If you have mould or mildew on any surface, then it will need to be treated.

 

Step 3 – Fill Any Holes

There can’t be any holes in your basement or cellar walls. So, fill everything with a good quality masonry filler.

 

Step 4 – Paint

Apply two coats of a specialist paint to finish.

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Preparing your Basement for Painting

 

The first thing you need to do is ventilate your room the best you can, and then acquire appropriate PPE. I’d suggest gloves, a mask, and eye protection. Regardless of how well you manage to ventilate, you’re still going to be working in a dirty room with some hard-core products.

You should then remove any loose material from the surfaces you intend to paint. A scraper will help with old paint or loose stone. I also scrub basement walls and ceilings with a yard brush to remove dust and debris.

Next you should fill any holes in your basement using a good quality masonry filler. You need to do this now because if there are holes in your painted surface, then water will still get into your basement, and you will have damp issues.

Opt for a filler that dries rock hard, as some of the others remain porous and can hold onto water. There are a couple of different products I can recommend for this. The first is Filltite Rapid Drying Exterior Filler, which is easy to use, dries quickly, and the repair will last.

But my absolute favourite is Toupret Murex (now called “Rock Solid Filler”). This is cement based and will adhere well to bare stonework. Simply mix with water until you achieve a smooth paste, then apply to your basement walls. Allow to dry for 48 hours before painting over.

Murex is quite difficult to sand, so try and fill flush where possible. But other than that, it’s easy to use and will not fail on you.

The best filler to fix peeling paint

Cleaning Basement Walls Before Painting

 

You’ve now done most of the preparation in your basement, but you still need to clean contaminants and tackle any mould patches.

Cleaning is very important. If you don’t do it properly then the paint will sit on top of dirt rather than adhering to the brick or stonework.

If it is just dirt on your basement walls, then good old-fashioned soapy water and elbow grease will do the trick.

If you need something a little stronger, then I recommend Zinsser Universal Degreaser and Cleaner. This is reasonably priced and comes as a spray. Simply apply it to dirty surfaces, leave for a moment, then wipe clean.

It is a very strong product, so wear your mask and take regular breaks if using it for a prolonged period. Let the vapour in the basement dissipate before cracking on with the rest of your work.

Zinsser Universal Degreaser and Cleaner is very Effective! It cuts through basically anything, so the surfaces in your basement will be clean enough to paint.

the best cleaner for basement walls

If there are patches of mould in the basement, then you will need to treat that too. Otherwise, there’s a good chance it will come back.

Luckily, Zinsser has a product called Mould Killer and Remover, which is very easy to use. Wear your mask, spray it on, leave to dry, then you’re ready to paint. Dead easy.

an agent to kill mould in a basement before you paint it

The Best Paint for a Basement

 

As already alluded to, the paint in a basemnt needs to be capable of holding back water and keeping the room dry. The only paint I know that can do that is Zinsser Watertite.

For best results, Watertite needs to be applied directly to the block, brick, or cement in your basement. You can paint over previously painted surfaces with it; however, the existing paint becomes the weakest point in the paint system and can affect adhesion,

Providing you get your prep right in the basement and you apply Zinsser Watertite directly to the brickwork, it will withstand up to 34 PSI of water pressure (which is the tire pressure in my van!). You can apply it to dry or damp surfaces, it prevents efflorescence (salts coming through the wall), it’s alkali resistant, and it even contains a fungicide to prevent future mould growth! (can you see now why I say Watertite is the best paint to use in a basement?)

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It is an oil-based product but it has low odour, so you won’t struggle with the fumes (but keep it well ventilated just in case). Watertite is very sticky, and you need to apply thick coats for it to achieve the optimal performance. This makes application slow going.

Use a 2- or 3-inch brush with synthetic bristles and a thick stock (click here to see a good option). Get loads of paint on, and really work it into every pinhole. Miss any, and water will still get into the basement.

You can also apply Watertite with a 9-inch long-pile paint roller. Work in sections of around 1 metre square, and then use your brush to work it into the pin holes.

Zinsser Watertite is touch dry after around an hour and recoat after 4 hours. Your basement walls will need two coats for it to be effective, but the second coat is easier to apply. You can simply cut in with a brush, then roll walls as you would with any other paint.

You will use a lot of paint to double coat even a small basement with Zinsser Watertite. You’re looking at a coverage of around 2 metres square per litre for each coat, so make sure you order enough to begin with.

Zinsser Watertite Waterproof Paint in a basement

FAQs

 

Can I use regular interior paint for my basement walls?

Regular emulsion alone will not withstand the conditions in a basement. However, if you apply two coats of Zinsser Watertite to your basement walls, you can then use emulsion as a finish coat. I’d recommend using an anti-mould paint to help stop future mould growth.

 

Do I need to prime the basement walls before painting?

If using Zinsser Watertite, you do not need to prime your basement walls before painting.

 

How do I deal with moisture or water issues in my basement before painting?

If your basement walls are wet, you can ventilate the room and use a couple of portable heaters. This will dry the walls while you paint. However, there are not many paint systems on the market that will last on damp walls. This is why I recommend painting with Zinsser Watertite.

 

Can I paint over existing mould or mildew in the basement?

Mould or mildew needs to be treated before you paint your basement. Get yourself some Zinsser mould Killer Spray.

Final Thoughts

 

Now you know how to paint a basement. Not just “a quick freshen up”, but if you carry out the work the way I’ve explained it, you’ll turn a dank, mouldy space into a clean, dry room which you and your family can use.

I know Zinsser Watertite is a specialist paint and it’s time consuming to apply, but there really is no better product. The conditions in a basement don’t lend themselves to being painted, so standard emulsion or masonry paint on their own will fail over time.

Updated May 16, 2024 | Posted Nov 15, 2023 | 0 comments

About the Author

About the Author

Mike Cupit has been in the decorating industry since 2002 and has mostly worked as a Trade Decorator in the domestic sector (peoples’ homes). Self-proclaimed “product geek”, Mike has a passion for paint and decorating tools. Mike now spends most of his time testing paint products and tools, comparing them to similar products on the market, and blogging about the industry in general.

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