Skylights – A homemade shallow box-shaped acrylic condensation cover for dome installations

Acrylic or polycarbonate dome skylights come in various sizes today. Traditional ones, however, are square to rectangular in shape and measure about 5 “tall. They can range in width and length from 12” to 36 “, and are 1/8” thick.

These domes can be mounted on wooden curbs (2×2 “to 2×6”), around which the roof tiles will be caulked or thin metal flashing will be placed to prevent any rain leakage around them. These domes can also be surface mounted directly on the tar paper and wood sheets directly under the shingles.

In the latter case, the surrounding dome shingles are laid directly over their flat outer flanges similar to the way shingles are commonly laid over the flat metal of roof vents, furnace chimneys, vents. sewer, etc. This installation minimizes the height of the dome.

Problem. Either way, or no matter how the domes are mounted, they can and will produce unwanted condensation and similar leaks, even if they have an internal plastic screen inside them. These domes are also vulnerable to cracking from large hail, fallen tree limbs, earthquakes, or careless roofers. When these events happen, the skylights will also leak rainwater, in addition to forming moisture.

Solution. Construct and install a 5-1 / 2 “tall hard clear shallow box-shaped canopy over the dome in the roof. This canopy will act like a storm window by withstanding most of the change in temperature and weather. formation of most of the condensation. For this item, a 20 “square dome (which includes a 1” flange on each side of the 18 “square dome), 5” high, and a surface mounted directly to the Roof sheeting will be used as an example to be covered with the box shaped storm hood Similar roofs can be built proportionally for other sizes of domes.

Materials and tools (total cost of parts: $ 50-90, depending on the availability of the acrylic sheet).

• One 2x6x96 “pressure treated board ($ 5)
• One 22×22 “sheet of 0.22” thick acrylic plexiglass ($ 25-60, depending on store available cut sizes). If the part must be cut from a larger sheet, leave the protective films unpeeled on both sides of the sheet until sawing is complete. Use a sharp, fine-toothed saw blade. Otherwise, let the output cut it to size.
• Twelve # 12×3 “Philips Screws
• 20 to 30 – # 8×1 “Philips Drywall Screws (Wide Head)
• A small tube clear silicone sealant ($ 4)
• Two tubes of silicone window / door putty similar in color to roof tiles ($ 8)
• Four 2-1 / 2 “L-shaped brackets perpendicularly flat ($ 5)
• Eight # 10×1 “wood screws (for attaching L-brackets to deck frame)
• Eight # 10×1-1 / 2 to 2 “wood screws (to attach L-brackets from frame to ceiling through shingles)
• A quarter of waterproof oil-based paint similar in color to roof tiles ($ 4)
• Tools: electric circular saw, electric drill, drill bits, Philips screwdriver, caulking gun, putty knife, rat tail file, paint brush

Roof construction.

1. Cut the 2×6 “board into four square corner pieces: 2 22” long and 2 19 “long.

2. Assemble the 22 “square box frame by sealing / securing the four corners with silicone waterproof window / door putty and 3” screws.

3. On what will be the bottom end of the bottom side, use the file to make at least three crescent-shaped groves for moisture drainage.

4. Paint both the inside and outside of the wood frame. Let it dry.

5. Lay the acrylic plexiglass flush against the frame.

6. Mark on the plexiglass where the screw holes will go, about 5 “around the top of the frame.

7. At each mark, drill a hole through the Plexiglass (only) wider than the drywall screw.

8. Next, using a narrow drill bit, drill 1/2 “deep holes in the center of the wood frame through the Plexiglass holes.

9. Remove the Plexiglass from the frame, noting how it fits into the frame.

10. Brush off any plastic or wood chips from the frame and Plexiglass.

11. Using the silicone caulk, add a narrow bead along each side of the frame drill holes around it.

12. Carefully place the Plexiglass back over the frame, aligning it with the original holes as appropriate.

13. Install the screws with medium torque so as not to break the Plexiglass. The putty will flatten out and spread between the plexiglass and the frame, sealing it.

14. Add at least one flat L-shaped bracket to each side of the frame flush with its underside with the 1 “wood screws.

15. Paint the brackets.

Installing the cover (the easy way).

1. While using the safety precautions, bring the entire deck up to the roof, assuming the roof is low slope and safe to walk on.

2. Center it over the dome skylight, square by square.

3. Attach the dome to the ceiling through the shingles with 1-1 / 2 to 2 “wood screws, depending on the thickness of the shingles.

4. Seal the bottom side of the top end and both sides of the cover with silicone window / door caulk. Seal the brackets and screws in the same way. Leave the underside of the lower end unsealed for drainage. It is a storm window.

5. If necessary, touch up the frame and supports with paint.

By installing the deck over the shingles, the wood sheets under the shingles are also protected from any moisture damage. This location also raises the canopy over the dome for adequate air space.

This covering will assume the formation of almost all condensation that would otherwise occur within the dome, none of which will pass through the dome into the house or under the tiles. It will also protect the dome from hail, falling tree limbs, and other damage. For more information on the types of skylights and their maintenance, check out these sites.