Metal roofing
Contents |
[edit] Introduction
Metal can be used as a roof covering in several different ways. The main forms are based on sheet-like panels, which may be flat or profiled, and either prefabricated, or formed on site, but metal can also be used to create shingles - formed into shapes similar to tiles, shakes or slates.
Sheet metal roofing is typically joined by standing seams or rolled joints. These have no exposed mechanical fasteners, but use a clipped, or rolled design which creates a distinctive projecting seam. This is a very flexible system that can be pre-fabricated or formed on site, and used to create straight or curved seams.
A wide range of profiled and corrugated metal roof panels (sometimes referred to as 'wriggly tin') are also available, historically associated with industrial buildings, as well as built-up roofing systems and trims and flashings to form valleys, ridges, rooflights, aprons, sills, corners, barges and so on.
[edit] Types of metal
Metal roofing materials are primarily manufactured from aluminium and steel, as they are economical, relatively easy to work, are durable and able to receive a number of different finishes.
Steel is heavier than other metal options but as a result is sturdier and can be coated with a range of finishes to provide protection against rust and corrosion as well as to provide colour. Aluminium is more lightweight and is resistant to rust. However, it is more expensive, and relatively soft and so is more prone to denting and marring.
Other metals available for roofing tend to be more expensive, and include:
- Copper: Has been used over centuries for roofs, is rust-resistant, and weathers naturally.
- Alloy roofing products: Formulated from more than one metal to tailor properties of strength and durability.
- Stainless steel: Does not rust or corrode.
- Zinc: Malleable, versatile and resistant to corrosion.
- Lead: Heavy and relatively expensive, but malleable and durable. Can be cut and formed on site to complex shapes.
Lead roof | Copper roof |
[edit] Advantages of metal roofs
The benefits of metal roofs can include:
- Life expectancy: Properly installed, a metal roof should have a long lifespan, being resistant to harsh weather, fire, mildew, infestation and rot.
- Weight: Metal roofing is generally lightweight compared with traditional tiles.
- Ease of installation: Most metal roofing materials come in sections,panels or rolls that are prefabricated off site and are relatively quick and easy to instal.
- Metal can reflect radiant heat from the sun, although it does become hot, and so, many systems include insulation, or a dead-air space between the metal and the interior.
- Minimal roof pitch: Most materials can be installed on gently pitching roofs without the danger of water penetration.
- Rain and snow shedding: Metal surfaces are hard and relatively 'slippery', meaning they tend to shed rain and snow relatively easily.
- Walkable: Most metals roofs can be walked on if necessary, although they may be slippery if wet.
[edit] Disadvantages of metal roofs
Disadvantages include the following:
- Cost: Metal roofing has a relatively high capital cost, although it can prove to be an economical investment due to its durability.
- Noise: Metal is noisier than some other materials when there is rain or hail falling on it. The drumming effect can be controlled by using materials that have structural barriers and the use of sound-deadening insulation.
- Denting: Metal can be prone to denting and scratching.
- Expansion and contraction: Metal expands and contracts as it warms and cools, which means that fastening systems must accommodate movement or else end up coming loose.
- Difficult to modify: As they are installed in large panels they can be more difficult to change.
- Theft: Some metals, such as lead have a high value, and are relatively easy to remove.
[edit] Related articles on Designing Buildings Wiki
- Aluminium.
- Cladding.
- Copper.
- Crinkly tin.
- Decorative metal ceilings.
- Domestic roofs.
- Failure of metals.
- Flashing.
- Galvanised steel.
- Lead.
- Long span roof.
- Major cast metal components.
- Metal.
- Metal composite panels.
- Metal profile cladding.
- Pitched roof.
- Roof coverings.
- Roof tiles.
- Shingle roofing.
- Structural steelwork.
- Types of cool roofs.
- Types of roof.
- Zinc
Featured articles and news
Licensing construction; looking back to look forward
Voluntary to required contractors (licensing) schemes.
A contractor discusses the Building Safety Act
A brief to the point look at changes that have occurred.
CIOB Construction Manager of the Year award
Shortlist set to go head-to-head for prestigious industry title.
HSE simplified advice for installers of stone worktops
After company fined for repeatedly failing to protect workers.
Co-located with 10th year of UK Construction Week.
How orchards can influence planning and development.
Time for knapping, no time for napping
Decorative split stone square patterns in facades.
A practical guide to the use of flint in design and architecture.
Designing for neurodiversity: driving change for the better
Accessible inclusive design translated into reality.
RIBA detailed response to Grenfell Inquiry Phase 2 report
Briefing notes following its initial 4 September response.
Approved Document B: Fire Safety from March
Current and future changes with historical documentation.
A New Year, a new look for BSRIA
As phase 1 of the BSRIA Living Laboratory is completed.
A must-attend event for the architecture industry.
Caroline Gumble to step down as CIOB CEO in 2025
After transformative tenure take on a leadership role within the engineering sector.
RIDDOR and the provisional statistics for 2023 / 2024
Work related deaths; over 50 percent from construction and 50 percent recorded as fall from height.
Comments