How to caulk baseboards – get a flawless finish without calling in a pro

Caulking baseboards might seem like one of those tiny decorating details that you can easily overlook, but do so and you will regret it. Anything that cuts down on housework has to be a good thing, and when baseboards are a good fit, you won’t find dust and grime lurking in gaps and crevices or drafts whistling through. 

Here’s how to seal up baseboards for a neat, professional finish.

How to caulk baseboards

You might already know how to caulk a bathtub or caulk a shower, in which case, you're just about good to go with caulking baseboards because the principles are much the same. All you need is a little patience, a few DIY tools and some handy tips. 

You will need:

• Decorator’s caulk (sealant) – Gorilla Waterproof Caulk & Seal is Amazon's top-rated best seller
• Cartridge gun
• Sealant remover (for previously caulked surfaces)
• Methylated spirit (denatured alcohol)
• Utility knife and/or razor scraper
• Needle nosed pliers
• Abrasive paper
• Wire brush
• Clean cloths
• Paintbrush
• Sponge
• Painter’s tape – Scotch General Use Masking Tape is highly rated on Amazon
• Caulk scraper – we like this General Purpose Plastic Razor Blade Scraper
• Protective gloves (goggles – optional)
• Dust sheet

1. Choose your baseboard caulk

There are lots of caulks out there, but unless you’re caulking an area that gets splashed decorator’s caulk is the one to go for. Unlike silicone caulk, latex and acrylic based caulk can be painted over so check the packaging says that’s the case. Although silicone caulk is great for bathrooms and kitchens, shrugging off splashes and moisture, it can’t be painted over.

2. Get prepped

If the baseboards haven’t previously been caulked, you just need to clean them up and you’re ready to go. But if there’s old caulk to remove, it needs to be softened and then removed. Put down a dust sheet, put on your protective gear and click here to check how to remove old caulk. 

Once you’ve stripped off any old caulk, use abrasive paper, a wire brush or pliers to remove any final bits then vacuum the baseboards carefully to remove any dust or stray hairs, paying attention to corners – a paintbrush can be used in any fiddly areas. To finish off, wipe the surface with methylated spirit (denatured alcohol) on a cloth.

If you’re hesitant about your caulking skills, you could run a row of painter’s tape along the base of the wall, and another along the upper edge of the baseboards. Leave a small gap for the caulk. But provided you work slowly and carefully, painter’s tape isn’t really needed. 

3. Start caulking

Once the surfaces are completely clean and dry, use a knife to cut the end off the caulk cartridge then trim the end from the nozzle at a 45 degree angle. It’s best to cut off a small amount at first to get a bead that’s about an eighth of an inch (3mm); if you cut too much there’s no going back. 

Attach the nozzle to the cartridge and put it into the caulking gun. Squeeze the handles to send the sealant along the nozzle. Taking your time, run a bead of caulk along the angle between baseboard and wall. If the wall is long, work in sections. Before putting the gun down, release the lever to take off the pressure or more caulk will leak out.  

To smooth the caulk, run a wet finger along the joint, or use a damp sponge. 

'If you're worried you might not be neat enough, use a smoothing/profile tool to remove any excess,’ says Beth Pearce, Category Manager for Construction and Internal Building at B&Q. 

Sometimes interruptions mean you can’t complete a large room in one go. 'If you need to stop the task and pick it up later, you can stop the caulk in the nozzle from hardening by inserting a tightly fitting screw,’ says Beth. ‘Once it's in place, run your finger around the screw head so that a film of caulk stops any air from getting into the nozzle.'

After caulking, the tape (if you used it) needs to be stripped off before the caulk dries. Leave the caulk to dry for the recommended time before painting.

Can I caulk between the baseboards and floor?

You can caulk between the baseboards and floor, and the method is the same, but not all floors should be caulked. It’s fine to caulk tiled floors and some wooden floors but many new wood floors are laid as a ‘floating floor’. This type of floor has a gap left around the edges allowing space for the timber to expand and contract when there are changes in heat and humidity. Sealing the gap is not recommended.

Do you caulk baseboards or paint first?

The idea is to caulk first so that when the wall is painted the paint can cover the caulking, making for a neat finish. However, on newly plastered walls it’s best to caulk after applying the first coat of watered down emulsion but before the top coat of paint.