STEP 1: PREP

Strapping

 

 

Roof strapping helps create a strong, even base for steel roofing panels. It allows the panels to sit flat and fasten properly, which helps prevent waviness and movement over time.

 

Strapping also creates a small air space under the metal roof, which helps moisture dry out instead of getting trapped. This reduces the chance of condensation, rust, and damage to the roof structure.

 

In short, strapping improves the look of the roof, helps it last longer, and supports a more reliable steel roofing installation.

How To Calculate Strapping

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When calculating wood strapping for a metal roof installation, there are three key rules to follow:

 

1. Double the strapping around the perimeter

All edges of the roof section being calculated must have doubled strapping. This includes the eaves, ridge, and both gable ends.

(Shown in red on the diagram.)

This added support is critical for fastening trim and ensuring a solid, long-lasting installation.

 

2. Install strapping at 24" on center

Run one row of strapping every 2 feet from the eave up to the ridge.

(Shown in dark blue on the diagram.)

This spacing provides proper support for the metal panels and meets standard installation requirements.

 

3. Double up strapping where boards do not span the full width

If the roof section is wider than the available strapping length (typically 12'-16'), a new column of strapping must be placed.

(As shown in the diagram, with two dark blue columns of strapping laid side by side.)

This ensures continuous fastening support and maintains structural integrity across the entire roof.

Underlayment

 

 

High-temperature underlayment is designed to handle the heat that builds up under steel roofing. Metal panels can get very hot in the sun, and standard underlayments may dry out, soften, or break down over time.

 

High-temp underlayment stays stable under high heat, helping protect the roof deck from moisture, leaks, and long-term damage. It also provides an added layer of protection during installation and in extreme weather.

 

Using the right underlayment is a simple step that helps your steel roof perform better and last longer.

How To Calculate Underlayment

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Underlayment is very easy to calculate, all you need to do is find the surface area of your roof!

 

You will need to convert to imperial if you took your measurements in metric, as rolls of underlay typically come in sqft measuements.

Our Team Is Here To Help

Getting this right isn't always easy - our team has years of experience and will happily assist with any questions regarding your project!

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