How far apart should roof purlins be?

The standard purlin spacing for metal roofs is four to six feet. However, most residential buildings have purlins spaced three to four feet apart. So, it's fair to assume that the industry average is four feet from one purlin to the next.

What is the minimum spacing of purlins?

In order for the sheets to be easily fixed to the purlins, as a rough guide they should be at least 50mm wide. When positioned, roof purlins should be spaced no further than 1.2 metres apart when using sheeting with a thickness of 0.7mm, and 1 metre when using 0.5mm sheeting.

How far can 2x4 purlins span?

Purlins to support roof loads are permitted to be installed to reduce the span of rafters within allowable limits and shall be supported by struts to bearing walls. The maximum span of 2-inch by 4-inch (51 mm by 102 mm) purlins shall be 4 feet (1219 mm).

What is the standard distance between purlins?

The purlin are ultimately used to fasten the roof steel providing a diaphragm effect, along with the siding, when properly engineered and installed. Spacing is typically 24″ on center in low snow loads and is reduced based upon truss span and snow load.

Can I use 2x4 for purlins?

Figure 3.6 For roof purlins recessed and turned edgewise, toenailing or hangers are acceptable ways of fastening purlins to rafters. 2x4 purlins may also be nailed on top of the rafters with one 60-d nail or attached with metal clips at each rafter.

Lean-to Conservatory Roof Replacement

How far apart should rafters be for a metal roof?

Standard industry roof rafter spacing is 12”, 16”, 19.2”, and 24” on-center, however other spacing may be used by a Structural Engineer. Depending on all contributing factors though, 16” and 24” are commonly used for most buildings. The wider the space between rafters often results in rafters of greater depth too.

How far apart should purlins be for metal roofing?

The maximum distance between purlins is five (5) feet on center. If your building site is in a region that is prone to heavy snow loads or high winds, then we may place your purlins closer together for added strength.

How do you lay out purlins?

Lay the first purlin at the ridge of the roof down to the chalk line beginning at either corner. Fasten the purlin with 16d common nails into each vertical rafter. Insert two equally spaced nails into the rafter. The rafters are generally spaced every 16 inches on center.

How far apart should purlins be spaced on a pergola?

Purlins are spaced about 3” apart. Will the unit be attached or freestanding? Attached would allow the pergola to attach to a home or building.

How far can a 2x6 span for a metal roof?

You'll see there's a maximum span of 16'-4" for 2x6's spaced 12" - so you might get away with it.

How far can a 2x4 span for a metal roof?

Spacing your 2×4 shed rafters at 24” on center limits the width of your roof. For light load roofs, 24” o.c. 2×4 rafters can span up to 7 ⅔'. For heavy loads, 2x4s can span up to 5 ½'.

What is purlin span?

Purlin Span. The span referred to is the distance between centers of the cleat bolts at each end of the purlin.

What should be the distance between roof trusses?

Roof trusses should be 24” apart, on center. Trusses are allowed to be closer together, at either 12” or 16” on center, but building codes allow for 24” on center spacing without using heavier duty fasteners for truss to wall connections.

Do you need purlins for metal roof?

According to Elite Steel and Supply, metal roof purlins are an important part of achieving excellent metal roofing installations that last for decades with low maintenance and unlikely repairs.

What is normal rafter spacing?

Builders aren't bound by standard rafter spacing measurements. But they do tend to space rafters in one of several industry-standard increments, typically either 12, 16 or 24 inches apart.

Which way do purlins face?

When placing Cee purlins into a roof the purlin should be bolted to the top side face of the cleat with the open C facing up the hill. With Zeds or Z section the purlin should be bolted to the lower side of the cleat with the upper flange facing up the hill.

Can you put metal roofing directly on rafters?

Metal roofing can be installed directly on open rafters. A metal roof can easily be installed directly over open rafters. Corrugated metal panels are relatively lightweight and can be purchased to fit almost any situation.

Should purlins be flat or on edge?

Putting the 2x4s on edge will give more strength between the trusses. Putting them flat will give more strength in terms of the purlins tipping over on the trusses.

Can purlins be laid flat?

Re: Purlins, flat or on edge

Not only will it sag, but it will become a giant sail when the wind blows and rip your roof off if you lay them flat.

Is a drip edge necessary on a metal roof?

A drip edge is not needed for metal roofing. If you make sure to overhang your metal roofing at least an inch, the drip edge is not necessary at the eaves and rakes.