Can Wood Filler Resist Rain? Here's What You Need To Know

Wood filler comes to the rescue when you need to fill gaps or holes to restore wood surfaces. However, you must use it properly to avoid mishaps that could lead to further damage. If you're still working to master the use of wood filler, you may have a few questions. A common one is whether this material can resist rain. According to Bob Beacham, House Digest's expert carpenter and remodeler, outdoor wood fillers can in fact resist rain. However, they aren't necessarily waterproof.

"Water resistant' is a common term and generally means that water splashes or occasional showers shouldn't be a problem," Beacham explained while speaking exclusively to House Digest. "However, if you expect full protection you should in theory choose a filler specifically described as waterproof. Is it important though? Wood itself isn't waterproof without a coating of some sort. There can't be many wood filler repairs that wouldn't then be painted or varnished." With this in mind, using a wood filler that is not labeled as water resistant shouldn't be much of an issue as long as you cover the wood with a protective coating after repairing it.

While speaking exclusively to House Digest, Beacham provided more detail on the proper ways to use wood filler to protect it from rain, even if the product itself is not waterproof. "Almost all wood fillers are 'paintable' except those that use silicone, so water-repellent sealers, varnishes, or paints can be used," he shared. "Once again, it's important to check that they are for outdoor use and provide a waterproof, not water-resistant, coating. Should it always be done? I can't think of a reason why you wouldn't."

At this point, you might be wondering what wood filler is the best to use if you need to worry about rain. According to Beacham, you have a variety to choose from. Big wood filler brands, such as Bondo, Minwax, Gorilla, Elmers, and DAP, typically offer water resistant formulas. If you would like to pick up a waterproof wood filler, Beacham warned you might have a bit more trouble finding it. However, keep in mind that, in mosts cases, these projects typically end with adding on a finish with protective properties. "2-part epoxy (often has 'wood repair' in the title) is usually strongest, but that still doesn't necessarily mean it's waterproof," Beacham added.

There are a few things you need to lookout for when shopping for the right outdoor wood filler for your project. "It's really important to check the description of each product to understand its characteristics and application," Beacham explained while speaking exclusively to House Digest. "There's lots of choice, so it's worth checking several before you decide."

The expert went on to detail some of the characteristics you can expect to see written on package labels. "Drying times vary," he shared. "Some are water-based (often latex) and therefore eco-friendly but by no means all. Bear in mind when staining or varnishing that the filler will absorb it at a different rate than the surrounding wood, so the filled area is likely to show. If you want to completely conceal the filler you'll probably have to paint over it." So, next time when you're working on a project, consider these tips when trying to understand the dos and don'ts for using wood filler.