Questions About Solar Roof Mounting and Waterproofing Worth Raising Before Installation

A roof can look suitable in a photograph while the installation still needs careful questions about attachment, structural support, penetrations, drainage and future access. Those questions are easier to answer before a quotation becomes a promise or work starts on the roof.

Start with the roof that is actually there

Ask the installer to describe the roof material, profile, slope, age and visible condition that were used for the preliminary review. Known leaks, cracked tiles, corrosion, previous repairs, extensions and planned renovation should be part of that conversation. A roof photo is useful evidence for a first discussion, not a remote structural verdict.

The U.S. Department of Energy's Building America Solution Center lists roof material, roof slope, weatherproofing, installation convenience and wind loading among the factors to consider when choosing a PV mounting system.^[1] The same questions are a sensible starting point in Malaysia, while the final method must follow the applicable local requirements and the roof's actual construction.

Malaysia's current self-consumption guideline also requires the relevant design, calculations, site plans, equipment layouts and structural drawings to be prepared and certified by qualified and competent persons. It says civil, building and structural work, where required, must be carried out, supervised and certified by qualified persons, and the site condition must be fit for the installation.^[2]

Ask how the load reaches the structure

Rails and clamps are visible. The load path is not. Ask where each attachment is intended to connect, what structural member carries it, how the spacing was chosen and how the edge, ridge and other exposed areas were treated in the design. If a structural review or drawing is required, ask who is responsible for preparing and certifying it.

The technical reference above notes that good roof-mount installations tie standoffs, lag screws or bolts into structural members, and that the mounting system should be compatible with the roof and PV module. It also says the additional loads on the system need to be considered and that the manufacturer's documentation should be checked.^[1] That is a reason to ask for the relevant drawing or product detail, not to guess a safe spacing from a web image.

Different roof materials need different attachment details. A tiled roof, a ribbed metal roof, a standing-seam roof and a low-slope membrane roof should not be treated as one generic surface. The proposal should name the roof condition it is designed for and state what changes if the installer finds something different on site.

Waterproofing is a detail, not a sentence in the quote

If the design creates roof penetrations, ask exactly how water will be directed around each one. The Building America guide describes flashing and seals as part of the anchoring system, and says the flashing should be integrated with the roof covering and underlayment. It also advises coordination with roofers before installation so the flashing material and installation method are agreed.^[1]

Useful questions to put in writing include:

• Where will the mounting points and cable entries be located?
• What flashing, boot, seal or roof-specific component is specified at each interface?
• How will the detail connect with the existing roof covering and underlayment?
• Who checks the work before the panels cover the attachment points?
• What is the agreed process if a tile, sheet, membrane or existing flashing is damaged?

Sealant may be part of a detail, but a line in a quotation saying “waterproofing included” is not a drawing. Ask to see the roof-specific method, the limits of the work and the party responsible for inspection.

Leave room for water, people and later work

Panel placement should be discussed alongside valleys, ridges, gutters, roof drains, vents, skylights, access routes and other equipment. The array may be electrically complete and still make later roof inspection or repair unnecessarily difficult if the layout leaves no sensible way to reach the surrounding roof.

Ask whether the proposal shows maintenance access, cable routes and the areas that must remain clear. Ask too whether a planned roof repair, extension or renovation changes the sequence. The current Malaysian guideline places responsibility for safe operation, inspection, testing and maintenance on the owner or occupier up to the point of interconnection, so the handover should make those responsibilities understandable.^[2]

Make the written proposal do some work

A useful proposal should identify the roof type reviewed, the mounting approach, the structural information relied on, the waterproofing detail, cable penetrations, access limits, testing and handover documents. It should also say what remains to be confirmed after the site assessment.

Inhome Solar's public service pages list solar installation, documentation and application support, operations and maintenance, and consultancy. Its public project page describes a sequence that begins with the latest bill, property type and roof photos, followed by site and electrical assessment, a written proposal, installation, testing and handover.^[3][4] That is a public description of the service scope, not a promise that an unnamed roof will be suitable or leak-free.

If the proposal also includes the current Solar ATAP route, ask which documents and technical assessment apply to the project and who owns each step. TNB's current page says Solar ATAP started on 1 January 2026, applicants appoint a Registered Photovoltaic Service Provider and the technical assessment study is a prerequisite for approval.^[5] Keep that programme work visible alongside, not instead of, the roof and structural questions.

What to send before a site discussion

For a useful first review, gather the latest roof photos taken safely from the ground or an existing access point, any known leak or repair history, available roof or building drawings, the property type and the latest electricity information. Do not climb onto a roof just to create a better photo.

Photos help an installer prepare. They cannot replace the site assessment, structural review or roof-specific waterproofing detail. Those items belong in the written scope before installation starts.

Updated 17 September 2026 · Inhome Solar field note