SEMCO field notes
diy guides.
Prep, application and troubleshooting for basements, roofs, showers, pools and more, written by the team that makes SEMCO.
29 articles
basementBasement Waterproofing Before Winter: A 7-Point Freeze-Thaw Checklist
A 7-point freeze-thaw checklist for basement waterproofing before winter: grading, cracks, reinforcement and a flexible membrane before the ground freezes.
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concreteHow to Waterproof a Concrete or Flat Roof Before Winter Rain
Concrete, built-up, and torch-down roofs leak differently than pitched roofs. Here's how to prep, seal seams, and coat a flat roof before...
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Is Drywall Actually Waterproof? The Myths DIYers Get Wrong
Green board, cement board, and paint don't make drywall waterproof. Here's what actually stops water, and how to seal it yourself.
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basementIs Your Basement Waterproofing Membrane Actually Failing? 7 Warning Signs
Peeling, chalky white powder, or a musty smell after basement waterproofing? Here are 7 warning signs your coating is failing, and how...
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roofMetal Roof Leaking? How to Find and Seal It Before Winter Rain
Metal roof leaking when it rains hard? Here's how to find the real leak point and seal it yourself with a flexible...
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comparisonLiquid Rubber Alternatives: A Longer-Lasting Way to Waterproof
A flexible, water-based liquid waterproofing membrane is the best liquid rubber alternative. See how it compares to rubber, masonry, silicone and sheet...
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fabric reinforcementWhat Is SEMCO Fabric Reinforcement and When Do You Actually Need It?
SEMCO Fabric Reinforcement adds tensile strength at floor-to-wall joints, corners, coves, and cracks over 1/4 inch, the spots a waterproofing coating fails...
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bathroomWhat Does It Cost to Waterproof a Shower Before Tiling? 2026 DIY vs Pro Breakdown
Professional shower waterproofing runs $450 to $2,500 depending on scope. A DIY liquid membrane and fabric reinforcement costs about $150 to $200...
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basementWater-Based Membrane vs Rubber-Based Coating for Basement Walls: Which One Actually Stops Water
Comparing water-based liquid membrane and rubber-based coatings for basement waterproofing: odor, UV exposure, cure time, and which one belongs on an exposed...
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deckWood Deck Waterproofing Membrane: The Complete Guide Before Fall Rains
Sealers and stains don't stop deck rot at the ledger board and joints. Here's how a liquid waterproofing membrane actually keeps a...
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bathroomShower Waterproofing Membrane: What Actually Stops Leaks Behind the Tile
Grout isn't what stops a shower leak. See the 3 spots where showers actually fail, and how to waterproof them with a...
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basementIs Black Mold on Concrete Basement Walls Actually Dangerous? What to Check Before You Waterproof
Dark staining on a basement wall isn't always toxic black mold. Here's what CDC and EPA guidance actually says, how to check...
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