Exploring Solar Panel Installation on Membrane Roofs

Exploring Solar Panel Installation on Membrane Roofs

When it comes to installing solar panels on membrane-covered roofs, there are various methods to consider. This blog delves into the pros and cons of different installation techniques to help you make an informed decision. But before diving in, let’s familiarize ourselves with roof constructions and relevant terminology.

Understanding Membrane Roof Types

Membrane-covered roofs encompass flat or pitched roofs protected by a waterproof membrane. Some common membrane types include:

1.Single Ply: Consisting of a single layer of plastic membrane like PVC, TPO, or rubber EPDM. Joints are typically welded or joined with adhesive strips.

2.Bituminous Membrane: Comprising one or multiple layers of bitumen membrane, often with a mineral coating for added protection. Joints are heat-sealed.

3.Liquid Applied Membranes: Applied as a liquid and cured to form a waterproof layer.

These membranes are versatile and can waterproof both flat and pitched roof structures.


Roof Construction Varieties

Roof constructions vary, but the main types include:

1.Cold Roof Construction: Featuring a ventilated timber roof deck beneath the membrane, with insulation typically between the structure and the vapor control layer.

2. Warm Roof Construction: Insulation is directly under the membrane, with a vapor control layer and supporting structure below. This construction is used for both flat and pitched roofs.

3. Inverted Roof Constructions: The waterproofing layer lies beneath the insulation, often referred to as an upside-down roof. Primarily used for flat roofs.

Methods of Solar Panel Attachment

Now, let’s explore how solar panels can be fixed to the roof structure, keeping in mind two essential criteria:

  1. Ballasted (Weighted) Installation:

  • Advantages:

– No penetration of the waterproofing membrane.

– Solar contractors can handle the entire installation.

– Often cost-effective.

  • Disadvantages:

– Possibility of movement in strong winds.

– Not suitable for taller buildings or certain roof types.

– Potential damage to the roof and structure due to cyclical movements.


  1. Bonded Installation:

  • Advantages:

– No penetration of the waterproofing membrane.

– Suitable for shallow-pitched roofs.

– Reduced weight on the structure.

  • Disadvantages:

– Risk of delamination and water ingress.

– Not ideal for steeper pitched roofs.

– Requires a roofing contractor for installation.


  1. Mechanically Fixed Installation:
  • Advantages:

– Highest resistance to wind uplift.

– Suitable for various roof pitches and building heights.

  • Disadvantages:

– Initial higher costs due to installation expenses.

– Potential for leaks if not properly installed.

– Attention needed to limit thermal bridging in warm roof constructions.

The above information is quoted from NICHOLSON’s blog Fixing solar panels to membrane roofs published on 17th October 2022.

Understanding your roof structure is crucial for choosing the most suitable solar panel installation method. Each approach has its benefits and drawbacks, so weigh them carefully before making a decision.  You can also contact Solaracks for any assistance.


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