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How To Waterproof Outdoor Lights?

If you’re worried about water ingress into your outdoor lights, this article will give you some actionable steps to follow to seal your outside lighting from the rain.

Any outdoor light sold in the US should be waterproofed safely in line with the UL Listings rating system. However, you can waterproof the seal between the light backboard and an exterior wall with water-resistant silicone caulk – which is available in hardware stores.

Let’s look into this subject in greater detail, and find out how to waterproof your outdoor lights for greater protection – and how to get rid of condensation inside lights. We’ll also consider if you can use indoor lights outside (hint: no don’t do it!).

Can Outdoor Lights Get Wet in The Rain?

If a product describes itself as being “for outdoor use”, it means it has been designed and made with weather in mind. Outdoor lights are generally better sealed, have a lower voltage, resist corrosion, and should withstand changes in temperature.

In the US, we have the UL Listings system, which rates lights depending on what type of environment they’re made for. There are three ratings: dry, damp, and wet. If your light is labeled “wet rated”, it’s suitable for outside. Don’t be tempted to think “well, it’s pretty dry where I live” and go for a damp-rated appliance: this simply isn’t suitable for outdoor use.

Outdoor lights also have an IP rating, which indicates how well the lamp is protected from dust and water. The IP rating consists of two numbers. The first shows grit and dust protection on a scale of 0-6, the second water protection on a scale of 0-8. In both cases, the higher the number, the greater the protection.

So, yes, provided they have a UL listing of wet-rated, outdoor lights can get wet in the rain. However, not all outdoor lights will manage a constant onslaught of heavy rain. Go easy on your lovely new outdoor light by choosing a relatively sheltered spot, such as under a roof overhang or protected from the prevailing wind.

Of course, this isn’t always possible. You may want free-standing lamps to illuminate your driveway or parts of your yard. If you want wall lights next to your front door, you can’t really choose which direction they face. Choose the toughest lights you can get, and make sure their build quality is solid: water getting into lamps is the biggest problem exterior lights face.

Make sure your outdoor lights are safe and protected, wherever they’re located, by making sure that they’re properly sealed. We’ll take a closer look at how you can do this.

How Do You Seal Outdoor Lights To Waterproof Them?

It feels counter-intuitive: we’re told as kids that we mustn’t mix water and electricity, and here we are, installing lighting in our yards. Happily, it’s straightforward to make sure our outdoor lights are safe in the rain, and one of the ways to do this is to seal them.

This makes sure that your lamp is extra-protected against water ingress. During a downpour, rain can make its way inside the light, even though the lamp’s been rated for wet outdoor use. You can give your outdoor lights extra protection by sealing them. 

We’re talking about exterior wall-mounted lights here, the ones that attach to your house wall with a backboard or plate. The weak point is often where the backboard is attached to your wall, as this can let in moisture. It can also let in bugs, spiders and general mess, so sealing it will help to protect your light against those, too.

You’ll need to pick up some water-resistant silicone caulk. This is easily available in DIY stores. Silicone is a tough, synthetic polymer that’s waterproof, has a high heat-resistance, and is breathable. Crucially for you, it’s also flexible and rubbery, so can be easily used with awkward shapes.

Silicone is a popular choice for plumbing jobs, as it creates a watertight seal that will last you for years. Some people say it can last for as long as 20 years, but to be honest, that’s not so likely in an outdoor setting. However, sealing your outdoor lights with silicone is a task you certainly won’t have to do very often.

Silicone caulk comes with an applicator gun, which holds the tube and allows you to gently squeeze the trigger, letting the caulk come out slowly. Make sure the tube is attached securely to the holder, before cutting off the top.

How Do I Seal The Gap Between The Outdoor Light & The Wall?

You have bought the silicone caulk and fitted it into its holder. What else do you need for your DIY job?

  • A ladder
  • A bucket of clean water 
  • A step ladder 
  • A drop cloth for your decking
  • A utility knife
  • Paper towels or a cloth to wipe up any spills as you caulk

Prepare before you start. Put down the drop cloth and safely open the step ladder. Pop a spare cloth or paper towels in your belt or pocket to quickly wipe up any errors. You’ll also need your utility knife to hand, as it’s a useful way of guiding the silicone caulk back into line if you go off-course.

And of course, the other key piece of prep is to read all the instructions before you start, so you can better visualize what needs to happen. Then, clean and dry the light and the wall, as silicone sticks better to a clean surface. Stick the caulk in its holster, cut off the end at a 34 degree angle, and you’re ready to seal.

  1. Slowly and steadily, start gently squeezing the caulk and applying it between the backboard or plate and the wall. Use a continuous stream, and always work top to bottom.
  1. Leave a small gap at the bottom: if any moisture does get in, it needs to be able to drain out. 
  2. When the whole gap has been caulked, dip your finger in the bowl of water. Use your wet finger to gently press in the caulk, all the way around. This gives a smooth, clean finish.
  3. That’s the caulking done! However, you need to clean up any spillages immediately, as the more set it becomes, the harder it is to scrape off.
  4. Store the remaining silicone caulk according to the instructions on the tube. This will also give you the curing time.
Waterproofing outdoor lights

How To Get Rid of Condensation & Water in Outside Lights

You’ve spotted moisture inside your lamp. This could be rain or condensation, and either way, it needs treating to prevent any damage to the lamp.

Condensation happens naturally when vapor becomes liquid on a cold surface – we’re all used to seeing it on windows and bathroom mirrors. However, it shouldn’t be happening inside your lamp if your lamp is properly sealed.

If you notice condensation or moisture inside an exterior wall-mounted light, you’ll need to make sure it dries, then seal it (as explained earlier). However, if you notice moisture inside a free-standing light, this could be a manufacturing defect: water shouldn’t be able to get inside. Speak to the store or manufacturer.

Can I Convert An Indoor Lamp into An Outdoor One?

The simple answer: no. It’s not worth the risk of benign electrocution. Outdoor lamps have a low voltage and secure, watertight casings, and of course, are wet-rated. Indoor lamps are never, ever safe outdoors.

If you have an indoor lamp that you think would look fabulous on your porch, how about placing it indoors, but on the window sill or on a table by the window? If you leave your blinds or curtains open, you’ll still be able to see the lamp, plus it will cast some light onto your porch or decking.

It can work really well the other way round, and you can use an outdoor lamp indoors. Their corrosion-resistant finishes and sealed electrics make them ideal for damp areas such as shower rooms and bathrooms. Just make sure the voltages match before plugging them in indoors, and that it hasn’t been treated with any anti-rust chemicals that shouldn’t be used on indoor items.


All outdoor lights sold legally in hardware stores and online in the US, should conform to certain waterproofing standards so they are safe to use. After all, water and electricity are not a good mix.

However, while your lights themselves may be safe from the rain, you may want to seal between the lighting backboard and the wall it is mounted on – and this can be done with water-resistant silicone caulk.

Taking such action should help further protect your outside lighting from the elements and prolong its life for years to come.

Mark H.

Homeowner and property investor Mark H. aspires to bring you the very best outdoor living content, based on his years of experience managing outside spaces. Read more >