Use ties to secure the trusses to the top plates of the backyard shed.

Where they are required, they should be installed on every other rafter where rafters are on 24-inch centers. Fit the trusses to the top of the roof, every 24 on center.

Collar ties are probably not needed if approved metal connectors were used to fasten the rafters to the ridge.

InterNACHI inspectors should not call out a lack of collar ties as a defect unless they know that collar ties were required in the jurisdiction where the home is located at the time the home was built.

They may or may not be required, depending on the jurisdiction. For a 16-foot span, 2×8 or 2×10 rafters would be appropriate, depending on the load and pitch of the roof.

In high-wind areas, uplift can tear a roof off of a house if it's not properly attached.Ĭollar ties and ridge straps should be installed on roof with a minimum slope of 3:12, a maximum wind speed of 100 miles per hour, and a maximum roof span of 36 feet. They must be spaced no more than 4 feet (1219 mm) apart. They must be at least 1 inch by 4 inches (25 mm by 102 mm). If collar ties or ridge straps are installed to connect opposing rafters, they must be located in the upper third of the attic space. Ridge straps are permitted to replace collar ties.

I'll get some pictures to you later.A collar tie is a tension tie in the upper third of opposing gable rafters that is intended to resist rafter separation from the ridge beam during periods of unbalanced loads, such as that caused by wind uplift, or unbalanced roof loads from snow. Lowes had the best price for galvanized roofing screws with a rubber washer: The advantage of wiggle wood is you can put the screw at the top of the wave on the corrugation which will reduce leaks.

Their picture is terrible so this is a picture from Home Depot : I am using 2'x12' galvanized metal corrugated roofing panels from Home Depot. I priced materials and I am going with a combination from Lowes and Home Depot. I put the joists 4' OC with perpendicular blocking spaced 2' OC. We burned about 3 1/2 last year (first year in house) so I'll have 2 years stored with a little margin. If I stack 6' high I'll have 9 cords under cover. My shed will have a covered area that is 24'x8' with a 2' overhang for a 28'x12' roof. If this ever happen under a woodshed it wouldn't be a big deal. Under the right moist and cool weather conditions I have seen water condensate on the bottom of bare metal roofing and watched it rain under the roof as it warmed up and the sun hit the metal roof. ,ĮDIT For anything but a woodshed I would still put felt paper or some membrane on the strapping directly under the metal. Step 1 Rafter spacing The rafter span is 3.000 m, and because this is a light roof, the far right column of NZS 3604:2011 Table 10.1 Rafters for all wind zones (see Figure 2) can be used for rafter spacings at 1200 mm (see Note 4 in Table 10.1). It makes it a lot easier to put the screws in once you get the sheets up on the roof.

Just make sure the metal roofing is all stacked exactly on top of each other figure out exactly where the screw holes need to be to line up with the strapping and drill the holes through all the sheets at once. One trick you can use for helping the metal roofing go on way faster and easier is to pre-drill the screw holes while the metal roofing is still in a stack. You'll save some $$$ using 1x4s over 2x4s. I can't see any advantage to using 2x4s for strapping unless your rafters are further apart then 24'. For metal roofing rafters 24' on center with 1x4 strapping (purlins) is pretty standard around here, with the strapping 16' on center.

Rafter spacing for metal roof shed