The short answer
Clear Debris and Drains
Start by removing leaves, dirt, and twigs from between deck boards and around any scuppers or drains. Blocked gaps trap water and speed up rot, especially in wet months. Use a stiff broom or a leaf blower to clear the surface, and pull out anything wedged in the joints.
Check that any gutters or downspouts near the deck are not spilling water onto the boards. If runoff from the roof hits the deck, it can pool in low areas. Redirect downspouts with extensions so water flows away from the deck edge. This simple step often solves the problem before any repair work is needed.
Inspect for Low Spots
After a rain, look for puddles that remain for more than a few hours. These are the low spots where water collects. Mark them with chalk or a piece of tape so you can see the pattern. Water that sits for days can soften wood fibers and invite mold growth underneath.
Use a long straight board or a level to check the deck surface. Place the level in several directions to find where the slope is off. A deck should slope away from your home, usually about a quarter inch per foot. If it does not, water will pool and eventually damage the framing.
- Look for puddles after a steady rain
- Mark wet areas with chalk
- Use a 4-foot level to check slope
- Test both along and across the boards
- Note any spongy or soft spots in the wood
Adjust the Slope
If the deck is flat or slopes toward the house, you may need to adjust the support posts or joists. For a raised deck, shim the posts with plastic or metal shims to raise the low side. For a ground-level deck, you might add a layer of gravel or sand under the frame to change the pitch.
This work can be involved, especially if the deck is large or attached to your home. A local water damage pro can assess the framing and suggest the right fix. They may recommend re-leveling the joists or adding a slight crown to the surface. Do not ignore the problem, as water will find its way into the substructure.
Add Drainage Solutions
For persistent pooling, consider installing a deck drain or a channel drain at the low edge. These systems collect water and direct it away from the deck and your foundation. You can buy plastic drain strips that fit between boards, or a trench drain that runs along the perimeter.
Another option is to improve the ground beneath the deck. If water pools on a concrete slab, ensure the slab slopes away. If the deck sits over soil, add a French drain to carry water away from the area. These solutions keep water from seeping into crawlspaces or basements.
Before you dig or cut, check for underground utilities. In Layton, you can call your local utility locator service to mark lines. This is a simple safety step. If the drainage work is complex, a pro can design a system that handles heavy rain without overflow.
- Install a channel drain along the low edge
- Add a French drain under ground-level decks
- Extend downspouts away from the deck
- Use plastic shims to raise low spots
- Ensure the ground slopes away from the house
Know When to Call a Pro
Some pooling is a sign of deeper issues, like a sagging beam or rotten joists. If you see cracks in the wood, hear creaking, or notice the deck pulling away from the house, stop using it and get an inspection. Water that has already seeped into the framing can weaken the whole structure.
Water damage pros can check the deck and the area below it, including crawlspaces, for moisture and rot. They can also dry out wet insulation or wood and remove damaged flooring if needed. Acting early prevents a small puddle from becoming a major repair. If you live in Layton, keep the number of a trusted pro handy for emergencies.
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Call (801) 383-0232 any time, day or night, and describe what happened.
Call Now (801) 383-0232Frequently asked questions
How do I find where water is coming from on my deck?
Watch during a rainstorm to see where water enters or pools. Check the deck surface, the seams between boards, and the edge where the deck meets the house. A flashlight at night can reveal damp spots. If water appears on the ceiling below, the source is likely a leak above.
Can I fix a low spot on my deck myself?
Yes, if the deck is sound and the low spot is small. You can add shims under the joists or use a self-leveling compound on concrete. For larger issues or if the deck is attached to the house, it is safer to have a pro assess the slope and framing. Improper fixes can trap water and cause rot.
What if water has already damaged the wood under my deck?
If the wood is soft, discolored, or has visible mold, you may need to replace the affected boards or joists. Water damage pros can remove water-damaged flooring and dry out the substructure. They can also check for mold and treat it. Ignoring damaged wood allows the problem to spread.