Home » Why you need underlayment installed by a roof plumber in Bayside

Why you need underlayment installed by a roof plumber in Bayside

Your roof is a worthy investment for your home or business.

It creates the insulation and coverage you need to be safe from various weather conditions and create a livable environment for your family or employees.

There are many layers to a roof that each has its own role, and today we’re talking about the importance of a roof underlayment that constitutes the layer before your metal roof.

Watermaster Roofing are expert roof plumbers who can fix, install, and assess your roof and all its components.

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What do you put under a metal roof?

Just like your floor underlayment and your mattress underlay, your roof also has an extra, protective layer called an underlayment.

A roof underlayment is a thin but strong blanket that sits over your roof decking that helps to support your home and roof.

The layers of your roof in order from the outside are:

  • Your metal roof – could also be made from shingles, terracotta etc.
  • Underlayment
  • Decking – The panelling material that makes your roof solid – not hollow. And gives your roof a flat surface
  • Rafters – the structural timber that gives your roof its shape
  • The ceiling

Can you walk on a metal roof with purlins?

Purlins are one such timber or metal plank that gets used to create the rafters for your home.

Decking and underlayment are important for plumbers and builders to be able to walk on your roof – without purlins, they would fall right through.

Is underlayment necessary for a metal roof?

Underlayment is essential for protection under your roof as it provides an extra layer of protection from incidents such as:

  • Damage from a storm
  • Water leakage
  • Thermal insulation issues

Without an underlayment, moisture can damage your decking and get into the other layers of your roof – making your house unstable.

If you do face instability or are worried about moisture and vapour damage, contact Watermaster’s roof plumbers in Bayside today.

Can you leave shingles under a metal roof?

If you’re considering metal roof installation in Melbourne, and currently have shingles as your roof, we’ll help you decide whether you can mount the metal roof over it or if you need the shingles removed entirely.

Your unique circumstances will help us determine the best course of action.

Can you install metal roofing directly to plywood?

If you fasten your roof to the plywood, then any decking that comes loose will affect your entire metal roof covering.

That’s why you need underlayment as an extra layer between your plywood decking and your metal roof.

Metal Roof Installation Melbourne


What’s the best underlayment for metal roofing?

There are a number of materials that can be used as your underlayment for your roofing in Mordialloc or other southeastern suburbs. And the material that best suits your home may depend on:

  • What type of roof you have – metal, corrugated iron, etc
  • The slope of your roof
  • How old your roof is
  • The texture of your decking
  • If it snows where you live
  • The climate of where you live
  • The humidity of where you live

We go through the main three types of underlayment materials and talk about their benefits.

Asphalt-saturated felt

This felt is soaked in asphalt – and sometimes tar – to create an insulated barrier between you and your roof.

This felt is made out of cellulose or fibreglass and is the most commonly used underlayment.

This felt absorbs water, giving it somewhere to go, not just deflecting it.

Non-bitumen synthetic

Usually made from polyethylene, polyolefin, or polypropylene, this covering is water-resistant and doesn’t absorb moisture, therefore discouraging the growth of fungus, moss, and lichen.

Rubberised asphalt

This product adheres to the decking for extra strength.

Rubberised asphalt is very flexible making it efficient for very hot and cold temperatures.

Because of this flexibility, rubber asphalt can be used to patch up isolated gaps of an underlayment already present.

New Metal Roof Installations


Who can I call to get an underlayment installation?

Watermaster Roofing are roof installers and specialists who install underlayment

Watermaster roofers are plumbers, installers, and specialists who service any home or commercial building roofing in Melbourne’s South-East.

We install metal Colourbond roofs and can carry out new metal roof installation and metal roofing replacement for your home or your commercial space.

Our team is registered with the Plumbing Industry Commission (PIC) and is qualified with the right expertise, experience, and deep knowledge.

Call Watermaster Roofing on 1300 576 075 or fill in the form to request an onsite inspection today.

2023-02-27T06:29:30+00:00 December 3rd, 2021|Metal roofing, Roof Plumbing|

Contact Watermaster
Roofing today!

Book an onsite inspection or give us a call to discuss roofing problems or your next roofing project.

Contact Thom and the team

Call 1300 576 075 Request a quote