Question 1

What is DexerDry?

Accepted Answer

DexerDry is a flexible weather strip, called a flange, that fits into the side grooves of grooved deck boards to create a DRY ZONE under your deck. Rain sheds off the top of the deck instead of dripping through the gaps between boards, which helps keep the area under the deck, porch or balcony dry. It comes on a roll and is cut to the length of each board. It is not rubber; it is a thermoplastic material.

Question 2

Is DexerDry a channel or trough under the joists?

Accepted Answer

No, DexerDry is not installed under the joists; it sits on top of the framing, in the grooves between the deck boards. Water sheds off the top of the deck and leaves at the board ends, past the drip edge, and through planned drainage gaps into gutters. Nothing hangs below the joists.

Question 3

Where does the water go?

Accepted Answer

Water runs across the top of the boards and sheds off the overhanging ends past the drip edge. Where a deck needs it, water also drops through small drainage gaps into gutters: at the house on decks with boards running away from the house, at seams and center boards on wide decks, and at the picture frame gap. Slope the deck 1/8 inch per foot away from the house so water keeps moving.

Question 4

Which DexerDry flange do I use?

Accepted Answer

Use the DexerDry profile made for your deck board brand, because every manufacturer's groove is a different size. The correct flange fits snug in the groove; the wrong one fits loose and leaves a gap. New profiles are added over time, so check dexerdry.com for the profile that matches your boards.

Question 5

Which decking brands does DexerDry fit?

Accepted Answer

DexerDry profiles are made for grooved boards from brands including Azek/TimberTech, Trex, Fiberon, Deckorators, MoistureShield and Wolf. Always match the profile to your specific board, and check dexerdry.com for the current list.

Question 6

What slope does the deck need?

Accepted Answer

Slope the deck 1/8 inch per foot, away from the house. Plan the slope when you frame the deck so water sheds off the surface and away from the house.

Question 7

What is the maximum joist spacing?

Accepted Answer

Joists must never be more than 16 inches on center. 12 inch or 16 inch on center layouts both work. Do not frame at 24 inches on center.

Question 8

Why leave a 4 inch gap at the end of the framing?

Accepted Answer

Leave a 4 inch gap at the end of the framing so the BlueClaw can hook the outer joist. With that space, one BlueClaw can cover a double joist at the edge, so you do not need a second compression tool there.

Question 9

How much gutter space does a perpendicular deck need at the house?

Accepted Answer

Allow 8 inches: 5 inches to the outside of the frame plus 3 inches to the next joist. This leaves room for the gutter at the house when the deck boards run away from the house.

Question 10

What lengths can DexerDry be used in?

Accepted Answer

DexerDry is used in 12, 16 and 20 ft lengths, matching most deck boards. It comes on a continuous roll and you cut it to the length of each deck board.

Question 11

Can I splice or glue DexerDry mid run?

Accepted Answer

No, never splice, glue or caulk DexerDry flange ends together; always install it in one continuous run. Deck boards also cannot be seamed in the middle of a run. If your deck is wider than 20 ft, split it with a gutter seam or a center board instead.

Question 12

How far does the frieze board extend past the framing?

Accepted Answer

Make the frieze board 3 inches longer than the framing on each side if you are building the DexerDry picture frame. Without the picture frame, it should extend at least 1 3/8 inch past the framing on both sides for proper drainage.

Question 13

What is the frieze board made of?

Accepted Answer

Use a 5/4 x 4 inch PVC trim board with a groove routed to match your DexerDry profile. It can be taller than 4 inches, and a length of decking can also be used. Keep it straight against the house, shim where needed, and flash it at the top so the siding laps over it.

Question 14

How do I clean the groove before inserting the strip?

Accepted Answer

Blow out the groove with an air compressor and wipe it with a paper towel to remove debris and moisture. Clean grooves are essential for a good seal. Check every board before you install it.

Question 15

What do I cut DexerDry with?

Accepted Answer

Cut DexerDry with a PVC pipe cutter or ratcheting PVC conduit cutter. These give a clean, precise cut. Cut each piece to the length of its deck board.

Question 16

What is the drip edge for?

Accepted Answer

The drip edge is a cut under each board end that stops water from wicking back under the board and into the grooves. Water naturally creeps along surfaces (capillary action). The drip edge breaks that path so water drops off the end instead. It is an essential step.

Question 17

Where is the drip edge cut?

Accepted Answer

Cut the drip edge on the underside of both ends of each board, 3/4 to 1 inch from the end and 7/16 to 1/2 inch deep, before the board is installed. The cut must go deeper than the groove. A circular saw works for board ends.

Question 18

Is a drip edge needed at the house on a perpendicular deck?

Accepted Answer

No, the house end does not need a drip edge as long as it is thoroughly caulked and flashed. Cut the drip edge only on the ends that overhang the frame by 1 3/8 inch.

Question 19

How much should the deck boards overhang the framing?

Accepted Answer

All deck boards must overhang the framing by at least 1 3/8 inch, with the drip edge about 3/8 inch outside the frame. The overhang works like the edge of an umbrella so water sheds off the sides instead of running back onto the framing.

Question 20

How much of the flange do I caulk?

Accepted Answer

Thoroughly caulk at least 1 inch of each end of every DexerDry piece, and 1 1/2 to 2 inches at the ledger on perpendicular decks. Work the caulk into the fins on the top, bottom and outer edge, and caulk all four corners. Caulk each row as you install it.

Question 21

Do I caulk the flange or the grooves?

Accepted Answer

Caulk the DexerDry flange itself, not the grooves of the deck boards. Caulk put in the grooves can get pushed out when the flange goes in, leaving hidden gaps that let water wick in.

Question 22

Which caulk should I use?

Accepted Answer

Use a clear caulk such as DAP UltraClear or Lexel Clear by Sashco, and do not use silicone caulk. Follow the caulk manufacturer's directions for weather and temperature.

Question 23

Which compression tools are recommended?

Accepted Answer

Use the DexerDry BlueClaw compression tool or the DeckWise Hardwood Wrench. Proper compression is extremely important, so use one of these two tools (sold separately). The BlueClaw is not mandatory, but it was made to work with DexerDry and gives consistent compression. Do not use a hammer and chisel.

Question 24

Can I use a hammer and chisel to compress the boards?

Accepted Answer

No, do not use a hammer and chisel to compress DexerDry. Use the BlueClaw or the DeckWise Hardwood Wrench to get proper, even compression.

Question 25

How do I set up a new BlueClaw?

Accepted Answer

Before first use, reverse the BlueClaw head 180 degrees using two 7/16 inch wrenches, then leave the bolt slightly loose so the head moves freely. Clamp the handle to a work surface with the claw up, loosen the smaller nut and bolt, lift and flip the head, reinsert the bolt and snug it without locking the head. The box includes two spare nuts and bolts.

Question 26

What is the joist sled?

Accepted Answer

The joist sled is a shop-made upside down T, about 20 inches long, that lets the BlueClaw work close to the house. Build it from scrap and use it with the BlueClaw for the first three boards, working from the center of the deck outward.

Question 27

How is the BlueClaw beater board made?

Accepted Answer

Rip a 42 inch 2x4 in half and mark an X 9 1/2 inches from each end. Place the X over the joist you are fastening. The offset gives steady pressure along the board.

Question 28

How many screws per joist?

Accepted Answer

Drive two screws per joist on every board, starting at the center of the deck and working outward one joist at a time. Keep the board compressed at each joist as you fasten it, and finish each board before starting the next. Use Starborn top mount screws with color matched plugs.

Question 29

Do I need to pre-drill?

Accepted Answer

Pre-drill composite decking with a 3/16 inch bit; PVC decking does not need pre-drilling. Always follow the instructions on your screw package.

Question 30

Can hidden fastener clips be used?

Accepted Answer

No, DexerDry sits in the groove the clips would use, so boards are fastened with Starborn top mount screws with color matched plugs. The plugs give a clean, hidden fastener look.

Question 31

When do I install the plugs?

Accepted Answer

Install the plugs as soon as you can, before rain, snow or debris gets into the screw holes. Use the color matched plugs that go with your Starborn top mount screws, and do the ones near the wall first on perpendicular decks.

Question 32

How do I compress the last board?

Accepted Answer

Screw a scrap 2x4 to the box framing as a jig and use it to push the last board tight. Compression tools cannot reach the last board. Long structural screws (such as LedgerLOK) with large washers work for the jig. Fasten the board while it is compressed, then move along the board.

Question 33

What is the picture frame drainage gap?

Accepted Answer

Leave a 1/8 inch gap between the deck board ends and the picture frame so water can drain. Miter the last board 1 5/8 inch from the tip and use 1/8 inch spacers where the screws land.

Question 34

How are fascia boards bumped out?

Accepted Answer

Install 1 1/2 x 1 1/2 inch blocks every 12 to 16 inches to bump the fascia out. The blocks support the picture frame and leave room for water to drain. Install the side fascia first, then the front.

Question 35

How do I flash the wall on a perpendicular deck?

Accepted Answer

Set an L shaped flashing (copper works well) into caulk where the decking meets the house, running about 3 1/2 inches up the wall. Run beads of caulk along the corner, the deck surface and the house, press the flashing into the wet caulk, cover the wall flashing with flashing tape, then install the trim board on top.

Question 36

What are the micro gutter dimensions?

Accepted Answer

Bend the micro gutter with 1 1/4 inch nailing flanges, 2 1/2 inch sides and a 2 7/8 inch bottom. It is a U shape made on a metal brake and fits a 3 to 3 1/4 inch gap in the framing.

Question 37

Can an aluminum gutter touch pressure treated lumber?

Accepted Answer

No, put a barrier such as Grace Vycor Plus or protective tape between aluminum and pressure treated lumber. Direct contact causes a reaction that breaks down the aluminum. Copper can touch treated lumber and is suggested for best results.

Question 38

What downspout size do I need?

Accepted Answer

DexerDry does not specify a downspout size; size and route it for your project. Drill a hole for the downspout in the micro gutter with a hole saw, and check with your builder or local code for sizing and routing.

Question 39

How do I handle a deck over 20 ft?

Accepted Answer

Split it into smaller decks with a seam gutter or a center board with a gutter on each side. Boards and DexerDry max out at 20 ft and cannot be spliced, so frame a 3 to 3 1/4 inch gap for a micro gutter, or use a center board, and gap the decking about 1/4 inch at the gutter.

Question 40

What gap goes at a center board?

Accepted Answer

Leave about 1/4 inch between the deck board ends and the center board. That gap lets water drop into the gutter below.

Question 41

How many center boards does a 60 ft deck need?

Accepted Answer

A 60 ft wide deck needs two center boards; repeat a center board every 20 ft. One center board with two gutters gives you a 40 ft wide deck.

Question 42

How are inside corners done?

Accepted Answer

Miter the frieze board at the corner, cut the DexerDry strip at the same angle, and caulk and flash every frieze board joint. Where two decks meet at a corner, add a gutter where they intersect. Do not glue or caulk DexerDry flange ends together.

Question 43

How do I test the deck?

Accepted Answer

Run water over the finished deck; it should flow across the boards and off the edge. Check that water sheds off the ends and drains through any gutter gaps.

Question 44

Can I power wash a DexerDry deck?

Accepted Answer

No, do not power wash; clean DexerDry with simple soap and water. Avoid solvents, abrasive cleaners and aggressive cleaning products, which can damage the product and void the warranty. A broom handles most everyday cleaning.

Question 45

Should I use joist tape?

Accepted Answer

Use joist tape as a flashing overlap at the house on perpendicular decks. Elsewhere, DexerDry keeps water on top of the boards. Follow your local code and builder's practice for any other joist protection.

Question 46

Can I put a ceiling under the deck?

Accepted Answer

Yes, use a vented vinyl or PVC soffit that allows airflow; wood ceilings are not recommended. Provide at least 1 1/2 inches of continuous ventilated screen at the fascia, or use a vented soffit throughout.

Question 47

Does DexerDry take longer to install?

Accepted Answer

It takes longer than a standard deck because of the extra steps, but builders find it comparable to installing an under-deck drainage system. Plan time for cutting drip edges, caulking each row and compressing each board.

Question 48

What order should I watch the install videos in?

Accepted Answer

Start with Installing Coilable Dexerdry, then Installing Dexerdry, Drip Edge, Decks That Span Over 20 ft Parts 1 and 2, and Perpendicular and Inside Corners. Find them under the Instructional Videos tab at dexerdry.com and watch them in the order listed there. Read the written instructions too.

Question 49

What roll sizes are available?

Accepted Answer

DexerDry comes on a 240 ft continuous roll, about 120 sq ft of deck, plus a smaller roll of about 50 ft for finishing a project. Check dexerdry.com for current roll sizes before ordering.

Question 50

What is coilable DexerDry and how is it different from the original?

Accepted Answer

Coilable DexerDry is the newer, flexible version that comes on a roll and installs the same way, with most of the same tools, as the original. Because it is flexible, it depends on proper compression between boards to seal.

Question 51

Why does DexerDry have to be compressed?

Accepted Answer

Coiled DexerDry is flexible and depends on tight compression between boards to seal, so tight is right. If the flange is not properly compressed and caulked where shown, the deck will leak. Use a recommended compression tool on every board.

Question 52

How do I use the DeckWise Hardwood Wrench with DexerDry?

Accepted Answer

Lock the wrench onto a joist and it holds the board compressed hands free while you drive the screws. It works on single or double joists and can be set up for left or right hand use. On a long board, it can hold one end tight while you compress the center.

Question 53

Can I use a Stanley Board Bender?

Accepted Answer

Use the BlueClaw or the DeckWise Hardwood Wrench; those are the compression tools DexerDry recommends. Proper compression is critical, so stick with a recommended tool.

Question 54

Can I use another cam style deck tool to compress the boards?

Accepted Answer

Use only the recommended compression tools: the DexerDry BlueClaw or the DeckWise Hardwood Wrench. Other tools may not give the even compression DexerDry needs.

Question 55

What is the BlueClaw?

Accepted Answer

The BlueClaw is DexerDry's own compression tool, designed to press deck boards tight against the DexerDry flange. It hooks the joist, and its large plate presses a 2x beater board to push the board tight. It is sold separately.

Question 56

How do I hold the BlueClaw while screwing?

Accepted Answer

Hold the handle down firmly with one hand and drive two screws per joist while keeping the pressure on. Work from the center of the deck outward, always press against a 2x beater board, and wear safety goggles.

Question 57

What safety gear do I need?

Accepted Answer

Wear safety goggles and the usual safety equipment, especially when using the BlueClaw. Safety glasses belong on your tool list for the whole install.

Question 58

How do I install the first piece of DexerDry?

Accepted Answer

Starting at one end, press the flange firmly into the routed groove of the frieze board, cut it to length and seat it with a rubber mallet. Then caulk both ends before setting the first deck board.

Question 59

How do I seat the strip without damaging it?

Accepted Answer

Rout a groove a little larger than needed into a scrap of decking and use it as a block to tap the strip into place. It is handy throughout the job whenever you seat DexerDry against an installed board.

Question 60

Why do the ends of the DexerDry need caulk?

Accepted Answer

Caulking at least 1 inch of each end stops water from wicking into the board grooves at the ends. Work the caulk into the fins on the top, bottom and outer edge of the flange. Proper caulking is essential.

Question 61

How do I caulk at the ledger on a perpendicular deck?

Accepted Answer

Run a generous bead along the ledger under the flange corner and another on top of the flange against the house, and caulk all four corners of both ends. Caulk 1 1/2 to 2 inches of the flange ends at the ledger. Caulk one board at a time and have the next board ready. Let the caulk ooze as you compress, and clean up the excess, preferably after it dries.

Question 62

Why use a beater board?

Accepted Answer

Always put a scrap beater board between the mallet or compression tool and the deck board so you do not damage the board edge or groove. Use it throughout the install, and improvise a smaller block near the end of the deck.

Question 63

How do I install the first deck board on a parallel deck?

Accepted Answer

Tap the first board onto the frieze board strip with a mallet and beater board, compress it, and drive two screws per joist from the center out. Cut the first board to exact length, confirm the 1 3/8 inch overhang, and keep it perfectly straight along the house, since a straight deck depends on it.

Question 64

What is the order for each row of boards?

Accepted Answer

Seat the strip in the groove of the board you just installed, caulk both ends, set the next board, compress it and screw it down, then repeat. Work from the middle of the deck outward, one joist at a time.

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