I wish we’d done this earlier because it’s actually really easy to widen deck boards – I thought we’d have to do major work to fix tight deck boards.
What Happens if You Don’t Space Deck Boards?
When the original owner of our lakehouse built the deck, he really pushed the deck boards close together. Maybe the decking boards expanded after he built it? Or maybe he didn’t realize deck boards need a gap between them? Either way, it caused problems. When it rained or snowed, water could never properly drain from the deck. In hindsight, this should have been obvious to me because the deck was covered in mildew when we bought the house. But I’d never lived in a house with a deck in my life, so I didn’t clue in.
If your deck boards are too close together, it can even lead to wood rot. In addition, deck boards need room to expand and contract, and without this space the wood can start to buckle or crack.
When we first bought the house and saw the mildew, I didn’t realize the deck boards were the problem. The deck looked like a normal deck! In 2014 I scrubbed the deck thoroughly, prepped for staining, and stained the deck grey.
I was disappointed when, a few years later, the deck stain looked like crap again. In 2018, a lot of the stain had just worn off and the mildew was back:
So I scrubbed it again and applied an opaque black stain. By this point, I suspected the deck boards were the problem but I thought it would be such a huge job to widen the deck boards. I hoped that if maybe, I got better stain, it would be fine… Plus we were getting the exterior renovated at this time, so it was a scramble just to get the deck stained before the snow fell.
By 2021 it looked like this (I snapped this photo after we widened the deck boards, to show you how the deck stain wore off):
So we finally decided to widen the spaces between the deck boards, before staining it black again. I sanded any loose and peeling bits of stain with an orbital sander while hubby went about widening the deck boards. Here’s how we did it – and how you can easily widen deck boards too!
Supplies to Widen Deck Boards:
- Circular saw
How to Widen Deck Boards:
First, you don’t need to remove the deck boards to widen the gap between them. Just take a circular saw and cut in between the boards. Sounds scary, right? Envisioning yourself veering off course and destroying the deck? All you need is a makeshift guide to keep the circular saw in line! I’ll explain how in the next section, but here are the rest of our steps:
- Clean the deck crevices of debris (a broom or leaf blower helps)
- Wear knee pads and hearing protection
- Hack your circular saw with our easy steps below
- Adjust the blade depth to cut through the crevice the entire board depth – but not so deep that is cuts the cross pieces under the deck boards
- Then simply run the circular saw between all of the deck boards
How to Make a Saw Guide to Widen Deck Boards:
You can buy a gizmo for this, but we couldn’t get info on shipping to Canada so we ended up just hacking a solution for ourselves. Hubby already had a piece of plywood attached to our circular saw (he got it from his dad like that). You can see in the photos that it is just screwed on.
With this plywood base, which you can easily make with a scrap of wood, we were able to add a single screw in front of the blade, screwed down to just short of the depth of the existing groove:
That simple hack acted like a guide as hubby slid the circular saw along, to make sure the saw didn’t go rogue and cut across the deck boards. You might have to adjust the screw depth if it gets caught on bits of stuff jammed in the crevices. An afternoon of cutting, and we had a 1/8″ gap between all of the deck boards:
What Kind of Saw Blade Did We Use?
First, use a new blade or this will take forever. Hubby tried it with some older blades and was not getting anywhere, so we bought a fresh blade and the job went so much more quickly.
For blade choice, many different saw blades would work. Hubby picked a blade with a low tooth count (40) because it cuts faster – although it does make a slightly rougher cut. This didn’t need to be a fine cut (like for furniture or fancy projects). You can see the cuts aren’t perfect but we felt that fast was better than perfect for this job. When I was sanding the deck, I could have sanded those edges too, but we just want this project done so I can put our patio loungers back.
How Long Did it Take to Widen the Deck Boards?
We thought this task would take days, which is why we avoided it, but it took hubby only a few hours. Of course, the size of your deck makes a difference!
Did it Make a Difference?
Already I see a huge difference! We definitely have a nice 1/8″ gap between all of the deck boards now:
Here’s a before and after:
The deck dries so quickly now after it’s rained or washed. And it seems like gunk doesn’t pile up in the crevices between the deck boards anymore. But I am going to try to use my leaf blower more to make sure the bigger pieces don’t sit in there. We get a lot of pine needles and the like covering our deck, so I need to get better at keeping it clean.
I finished sanding any loose bits and managed to apply a clear deck primer since taking these photos, but now it’s been raining so often I can’t finish staining the deck. Ugh, this happens every year. I hate deck staining… I chose a black stain again and hopefully the deck primer makes a difference in how well it withstands the elements. I didn’t sand the deck down completely because the deck primer/stain I’m using doesn’t require it – but my father in law, a woodworker by trade, is dubious of my plan, lol.
Once the weather cooperates, I’ll share an update on the finished deck and also again after we’ve lived with the new widened deck boards for a bit. Fingers crossed I can take a nice long vacation from deck staining now that we figured out how to widen the deck boards…
Hopefully this is helpful for anyone who needs to fix tight deck boards. Don’t delay, like we did, because deck boards that don’t have gaps can cause major damage to the wood.
P.S. Don’t Forget to Pin for Later!