spray foam, 7 DIY Spray Foam Tips for a Smooth Application


Spray foam has a ton of uses as well as basic insulation – but it can look ugly when it’s not finished well.

Whether you’re plugging exterior holes, sealing outdoor taps, or even bonding rocks together for your water feature, a smooth finish is what you’re after.

Before you reach for the can of DIY spray foam to plug that annoying draft or fix a rattling pipe, check this quick guide to make sure you’re getting the smoothest finish possible.

Why Does Spray Foam Look Bumpy?

Spray foam offers a wide range of applications around the home. It’s a great product because it expands once it’s sprayed – then sets hard.

The lumps are created by the foam moving into small spaces and expanding to give it that telltale DIY knobbly appearance. You can paint the foam once it’s dry, but this won’t hide the overall surface.

Sometimes, a lumpy appearance is preferable – such as when using spray foam as an insulator inside walls. The lumps create air pockets to act as an insulator.

However, most DIY spray foam applications include things like filling small holes, stopping drafts, and preventing pipes from rattling. If you’re using spray foam that’ll be on show, a smooth finish is the best option.

Smooth Operator: 7 Tips to a Great DIY Spray Foam Finish

It’s surprisingly easy to get a smooth finish with spray foam. From proper preparation to working quickly, follow these spray foam tips to get the smoothest finish possible.

  1. Prepare for Mess

Spray foam is a pain to clean up – but you’re guaranteed to get a bit messy!

Wear protective clothing and have a safe space to put the spray equipment while you’re not working with it. This stops any excess foam spilling onto the floor or surfaces.

  1. Rent Proper Equipment for Big Insulation Jobs 

Hire proper spray foam insulation equipment if you’re filling crawl spaces, insulating your basement, or building new walls in your home.

The foam used will comply with building and safety regulations. Using proper equipment will give you the best finish, too.

  1. Ensure a Dry Surface

The foam won’t set properly if your working surface is wet.

Always work on a dry surface. You might need to put a dehumidifier in the room if you’re tackling a damp problem – otherwise, the surface won’t dry out well enough to work with.

  1. Invest in a Spray Foam Gun

When using a small spray foam can for tiny DIY jobs, add precision and reduce waste by buying an application gun. This holds the can for you and helps you to control the application with both hands.

They only cost a few dollars but could save you a lot in costly mistakes!

  1. Don’t Wipe Up Mistakes

If you drop the foam on the floor or spray it in an area that you don’t want it, wait until it’s dry.

You’ll be tempted to wipe it up straight away, but don’t! This’ll just spread it and make the mess worse. Once it’s dry, carve it off the surface with a knife, sand the area, and re-paint if necessary.

  1. Go Slowly

It’s easy to underestimate how much your foam will expand. This leads to overflow splurging out of nooks and crevices!

Go slowly and apply the foam in small increments. Wait a few seconds to allow the foam to expand before applying the next amount. This helps reduce waste and minimizes too much lumpy overflow.

Working slowly on large areas such as basement insulation also ensures an even coverage for the best result.

  1. Carve a Clean Finish

When your foam has set, use a knife to carve a flush finish on areas that will be on display. For a really smooth finish, such as visible areas on internal walls, use sandpaper to grind back the foam flush with the surface.

This also smooths minor lumps and bumps that make it easy to paint over to blend in with the rest of the wall surface.

Avoid More Remodeling and DIY Disasters

Getting a smooth finish on DIY spray foam is a small, but important, detail if you want a great overall look to your home.

From tiny details like smooth spray foam to completing huge renovation projects, the attention you pay to the finishing touches makes a difference to the end result.

Check out our blog for tons of hints and tips to achieving the best finish to every home remodeling project you’ve got in mind!

– This is a sponsored post and not written by the owner of this site.