Aluminium Fascia: Profiles, Specification, Installation, and Why It Is the Right Material for a Long-Lasting UK Roofline
There is a moment most homeowners hit where they have repainted the fascia boards for the third time in twelve years, watched the paint blister through the next winter, and finally thought: there must be something better than this. There is. It is called aluminium fascia, and once you understand what it is and how it performs, the question is less whether to use it and more why it is not more commonly specified on every domestic roofline replacement in the UK.
This guide is not a general introduction to what a fascia board does — there is plenty of that available elsewhere. This is the detailed specification guide for aluminium specifically: the profiles available, what each one suits, the alloy grade and finish quality that determine long-term performance, the installation requirements unique to aluminium that uPVC installers sometimes get wrong, the lifetime economics, and how to specify and order a complete system that will look sharp and perform reliably for the next four or five decades.
What Makes Aluminium Fascia Different From the Start
An aluminium fascia board is a length of 2mm aluminium sheet, brake-pressed into the required profile — square edge, bullnose, or other — and finished with a polyester powder coat baked onto the surface. It does the same structural job as a timber or uPVC fascia: it runs along the lower edge of the roof, covers the rafter ends, provides the fixing point for gutter brackets, and closes the front face of the eave.
The difference from timber is obvious. Aluminium does not absorb moisture, does not rot, does not harbour insects or fungi, and does not need repainting. The difference from uPVC is subtler but equally important. uPVC becomes brittle under sustained UV exposure. Its colour is extruded through the material and cannot be changed later. Its push-fit joint system uses rubber gaskets that harden and fail. And it expands and contracts more dramatically with temperature than aluminium, which puts ongoing stress on every joint and fixing in the system.
Aluminium handles the British climate with more composure than either of the alternatives. It expands and contracts with temperature, but predictably and in manageable amounts, and a correctly installed aluminium fascia system is designed to accommodate that movement without stressing the joints. The powder coat finish is baked onto the metal surface, which makes it fundamentally more stable than a painted surface, and the colour range is effectively unlimited because any RAL or BS shade can be specified.
Alloy Grade and Powder Coat Quality: Why These Matter Before the Profiles
Not all aluminium fascia is equivalent, and the differences that matter most are not always visible in a catalogue image. Before choosing a profile or colour, it is worth understanding what to look for in the base specification.
2mm Thickness as Standard
The standard structural thickness for aluminium fascia board in residential and commercial roofline applications is 2mm. This is not an arbitrary dimension. At 2mm, the board has sufficient structural rigidity to support gutter brackets and the load of a full gutter without flexing, and it handles the thermal expansion and contraction of the British temperature range without distorting between fixings. Thinner-gauge product may cost less but lacks the stability that makes aluminium fascia worth specifying in the first place.
Marine Grade Alloy for Exposed Locations
Standard aluminium alloy is the right choice for most inland UK locations. For coastal properties, riverside locations, or any building in a high-humidity, high-salinity environment, marine grade alloy provides significantly better corrosion resistance. The alloy composition is formulated for environments where salt-laden air would accelerate surface degradation on standard aluminium over time. The cost premium is modest and the extended service life in exposed conditions makes it a straightforward specification upgrade.
Architectural Grade Polyester Powder Coat
The powder coat on aluminium fascia is not a paint. It is a dry polymer powder applied electrostatically to the prepared aluminium surface and then cured in an oven at high temperature, forming a finish that is chemically bonded to the metal rather than sitting on top of it. Architectural grade polyester powder coating, which is the standard used on quality roofline products, achieves a fire classification of A2-s1,d0 under BS EN 13501-1. This non-combustible classification meets the requirements of Approved Document B for buildings above 11 metres and is increasingly the expected standard on commercial and multi-residential specifications.
The visual durability of quality powder coating is substantially better than paint. It resists chipping, surface chalking, UV fading, and peeling far more effectively than a conventional painted surface. A good powder-coated aluminium fascia will maintain its colour and surface quality for 25 years or more under normal UK conditions — considerably longer than painted timber, and considerably longer than the UV-degraded surface that characterises an aged uPVC fascia.
Aluminium Fascia Profiles: Choosing the Right Look for the Building
The profile is the cross-sectional shape of the fascia board — specifically the visible front face. For most UK properties it comes down to three main choices, each suited to a different architectural character:
Contemporary new builds, renovations, commercial
Most popular in aluminium. Suits anthracite & black.
Softly rounded lower edge
Suburban residential, traditional estates
Familiar domestic profile. Suits white & cream.
Decorative S-profile lower edge
Victorian, Edwardian, heritage properties
Pairs well with ogee guttering.
Properties with tall rafter ends or complex eave detailing
Available bespoke width in aluminium.
The square edge profile is a flat-fronted board with a clean right-angle at the lower edge. It is the most architectural of the three main profiles and the one that suits contemporary properties most naturally. On a modern new build with powder-coated windows in anthracite grey or black, a matching square edge aluminium fascia gives the roofline the same considered, geometric character as the rest of the building's design language.
Square edge is also the right choice for commercial and mixed-use buildings where a clean, professional finish at roof level is expected and where the decorative quality of a bullnose or ogee profile would be inappropriate. The visual simplicity of a flat board with crisp edges suits the scale of commercial rooflines in a way that more domestic profiles do not.
The aluminium fascia range from Online Metal Store Ltd includes square edge profiles in standard and bespoke widths, available in any RAL colour. For projects that specify anthracite grey or black throughout the roofline, square edge aluminium fascia in a matching colour is the most commonly selected product.
Bullnose fascia has a slightly rounded lower edge rather than a sharp right-angle. The softening of the lower profile is subtle — this is not a dramatically decorative feature — but it makes the board feel less austere than the square edge and more familiar to the eye on traditional UK residential housing.
Bullnose is the right choice for properties built in the 1970s to 1990s where the original timber fascia was likely bullnose in character, and where the renovation goal is a clean, modern replacement that maintains the visual familiarity of the roofline without looking like a commercial upgrade. It works across a wide range of property types and is the most broadly applicable profile for standard domestic roofline replacements.
Ogee and Heritage Profiles
Ogee fascia has a decorative S-shaped profile on the lower edge, echoing the moulded timber fascias historically used on Georgian, Victorian, and Edwardian properties. On heritage properties, particularly those in conservation areas or where the roofline character is part of the building's identity, a square or bullnose aluminium fascia can look too contemporary and too clean to sit comfortably with the rest of the architecture.
Cast aluminium and brake-pressed aluminium ogee fascia profiles are available for projects where the heritage character needs to be maintained or replicated. Combined with matching cast aluminium ogee guttering and round downpipes in textured black, an ogee aluminium fascia gives a period property a roofline that looks architecturally honest while providing all the performance advantages of aluminium over timber.
Specifying the Right Fascia Width: Measuring Correctly and Understanding What You Need
The width of the fascia board is its visible height — the vertical dimension of the face that runs along the roofline. This is determined primarily by the height of the rafter ends it is covering, not by any universal standard.
How to Measure the Required Fascia Width
With the existing fascia removed, measure the height of the rafter ends from the top of the rafter to the underside of the soffit level or wall plate. This gives the minimum depth of fascia needed to fully cover the rafter ends. Add a small allowance — typically 20 to 30mm — to ensure the board overlaps cleanly at both the top and bottom edges without exposing the rafter end.
On properties where the existing fascia is still in place, measure the visible face height of the existing board from the ground or a ladder. Note both the face height and whether the existing board has a significant return leg at the top — some fascia profiles include a horizontal return that engages with the roof covering or underlay felt, and this needs to be replicated in the replacement specification.
Standard Widths Available
Standard aluminium fascia widths typically range from 150mm up to 300mm in common stock sizes. Wider boards up to 400mm and beyond are available but may need to be specified as bespoke. The advantage of aluminium over uPVC for non-standard dimensions is significant: aluminium can be brake-pressed to any width to match a non-standard eave geometry precisely, without the need for site-cutting or packing that a fixed-standard uPVC board would require.
Bespoke Width Fabrication
For properties with unusually tall rafter ends, deep overhangs, or any dimension that does not match a standard width, aluminium fascia can be fabricated to the exact required dimension. This is one of the practical advantages aluminium has over uPVC for renovation projects on older or non-standard properties. Online Metal Store Ltd fabricate aluminium fascia boards to measure with typical lead times of three to five working days for standard colours, and can advise on profile choice and dimensions during the specification process.
How Aluminium Fascia Behaves During Installation: The Thermal Movement Rules
This is the section most relevant to anyone who has installed uPVC and is fitting aluminium for the first time. The two materials share the same basic installation sequence — fix to rafter ends, engage soffit, fit corner pieces — but aluminium has specific installation requirements around thermal movement that are different from uPVC and that, if ignored, produce visible problems.
A 3m length of aluminium fascia board expands and contracts by approximately 3mm between the coldest winter temperature and the warmest summer temperature in a typical UK climate. On darker colours — anthracite, dark bronze, black — the thermal range is greater because dark surfaces absorb more solar heat, and the movement can approach 4 to 5mm on a hot summer day in direct sun.
This is less movement than uPVC over the same temperature range, but it is still meaningful. Three millimetres of unconstrained expansion across a 3m board, multiplied across a full roofline of eight or ten sections, would cause significant problems if the system were fixed rigidly at every point.
The Floating Fix Principle
The correct installation method for aluminium fascia uses a combination of a fixed point — the dead fix — and floating fixings at all other positions. The dead fix is typically one centrally-positioned fixing per board length that prevents the board from translating along the wall but allows it to expand and contract symmetrically outward from that point. All other fixings are made through slotted or oversized holes that allow the board to slide freely relative to the fixing as it expands and contracts.
Oversized fixing holes should be pre-drilled to approximately 2mm larger than the fixing shank diameter. The fixing should sit in the centre of the hole at installation temperature, leaving equal clearance on both sides for the movement to occur in both directions. A fixing that is placed at the extreme end of an oversized hole leaves no room for movement in one direction.
Stainless Steel Fixings Only
All fixings into aluminium fascia must be stainless steel, either A2 or A4 grade. Using mild steel screws or nails creates a galvanic couple between the two dissimilar metals that accelerates corrosion at the fixing point. Over time, the mild steel fixing corrodes, stains the aluminium around the fixing hole, and loses grip. This is not a problem that becomes apparent immediately. It develops slowly over three to five years, and when it does become visible, the remediation is awkward and disruptive.
Stainless steel fixings used with aluminium are essentially inert from a corrosion perspective. The marginal cost difference between stainless and standard steel fixings is trivial relative to the installed cost of the fascia system, and there is no rational argument for using anything else.
Standard practice on timber and uPVC fascia involves fixing through the face of the board — visible fixings driven through the front surface. On aluminium, face nailing is a problem because the fixing head constrains the board at that point, preventing thermal movement. When the board expands, it has nowhere to go and the result is a buckled, rippled fascia that is visually obvious on warm days.
On aluminium fascia, fixings should be driven into slotted fixing flanges, through the return legs of the profile, or through concealed fixing positions where they do not constrain the face of the board. The system profile design determines where the fixings go, and this varies between manufacturers. For OMS fascia profiles, the relevant installation guidance specifies the correct fixing position and hole size for each type.
A 3 to 4mm expansion gap must be left between adjacent fascia sections at every butt joint. This gap accommodates the movement of the boards without the ends compressing against each other. The gap is covered by the union or joint trim, which slides over the gap and is fixed only at one side to allow it to move with the panels. The joint trim should not be fixed rigidly at both sides — it needs to float along with the thermal movement of the boards on either side of the joint.
Low-modulus silicone sealant applied at the joint and at corner trims accommodates movement while maintaining a weather-tight seal. The same principle that applies to gutter joints applies here: low-modulus silicone stays elastic under repeated thermal cycling, while standard silicone hardens and eventually cracks.
Corner Details: External, Internal, and Hip Returns
The corners and returns of the roofline are where most installation complications arise, and where the difference between a professional-quality finish and a mediocre one is most visible. Aluminium fascia systems include purpose-made corner pieces that provide a clean, pre-formed angle at each corner position.
At a projecting external corner of the building — the most common corner type on gable-ended houses — a 90-degree external corner piece is used to turn the fascia from one elevation to the next. This component is factory-fabricated from the same 2mm aluminium as the fascia boards, in the same profile and colour. It is fixed to the rafter ends or corner support structure and the run of fascia board engages into it from both sides.
The alternative — attempting to mitre-cut two fascia board ends at 45 degrees and butt them together at the corner — is rarely successful. The thermal movement of the boards pulls the mitre open over time, the joint becomes visible, and water can track behind it. Purpose-made corner pieces avoid all of this.
Internal corners, where the roofline runs into a re-entrant angle of the building, require internal corner pieces. These are less commonly encountered than external corners on standard residential properties but are found on more complex rooflines with projecting bays, extensions, or L-shaped buildings.
On hip-roofed properties, the fascia must follow the hip rafter angle at each corner, which involves a 45-degree return rather than a 90-degree turn. The corner piece for this configuration is either a factory-fabricated 45-degree mitre or a bespoke angle piece fabricated to the specific hip geometry of the building. This is another case where the fabrication capability of aluminium — able to be formed to any angle — gives it a clear advantage over standard uPVC profiles with limited corner fitting options.
Colour Selection and Roofline Coordination: Getting the Most From Aluminium's Colour Range
One of the strongest practical arguments for aluminium over uPVC in any roofline specification is the colour. uPVC has historically been available in a limited palette — white, cream, brown, and a small number of other shades. Aluminium can be powder coated in any RAL or BS colour, which opens up the full range of coordinated roofline design.
The Importance of Matching Across Components
A roofline that uses the same colour across all its components — fascia, soffit, guttering, downpipes, and any other visible aluminium elements — looks cohesive and deliberately designed. A roofline where the fascia is anthracite grey, the gutter is black, and the soffit is white looks like a collection of separate decisions made at different times by different people, even if each individual product is perfectly adequate.
Because Online Metal Store Ltd supply aluminium fascia, soffit boards, gutters, downpipes, and all associated roofline components in the same powder-coat colour range, specifying the entire roofline in a single matching finish is entirely practical. This is one of the most significant improvements aluminium makes possible over a mixed-material approach.
Common Colour Choices and What They Suit
White (RAL 9010 or RAL 9016) remains the most widely specified colour for domestic rooflines and suits traditional red or buff brick houses, white render, and pale stone. It is clean, familiar, and coordinates with most exterior colour schemes without demanding attention.
Anthracite grey (RAL 7016) has become the defining roofline colour of the past decade on renovated and new-build properties. Combined with grey window frames and dark cladding, it produces a cohesive contemporary exterior. On properties where the windows are already anthracite, matching the roofline to the same colour lifts the whole building without requiring any other changes.
Black (RAL 9005 in gloss or textured) suits heritage properties where the original cast iron roofline detailing was dark, and contemporary commercial or high-specification residential buildings where a strong dark perimeter at roof level is an architectural intention. Textured black particularly suits period properties where gloss would look too contemporary.
Beyond these three common choices, any RAL colour can be specified. Heritage stone tones, Chartwell green, dark bronze, and bespoke architectural shades are all achievable with a standard fabrication lead time.
The Lifetime Economics of Aluminium Fascia: Why Upfront Cost Is the Wrong Comparison
The most common objection to aluminium fascia is that it costs more than uPVC. This is true. The more relevant comparison is total cost over the life of the building, and on that measure aluminium looks considerably different.
Joint / bracket repair likely
Mid — deceptively costly over time
Higher upfront, lowest lifetime cost
The table above is a simplified illustration, but the underlying logic is straightforward. A uPVC fascia system installed for £2,500 on a standard semi-detached house, lasting 25 years and then needing replacing, has a total 50-year cost of £5,000 plus whatever inflation and labour cost increases apply by the time of the second replacement. An aluminium system installed once for £3,500, lasting 50 years with no repainting and minimal repair, has a 50-year cost of £3,500. Before any maintenance cost for timber, the aluminium has already won.
For landlords managing a portfolio, this arithmetic matters a great deal. For homeowners who intend to be in the property for a long time, it matters too. And for anyone who has already replaced their fascia twice and is thinking about what to do with it a third time, the case for finally switching to aluminium is hard to argue against.
What a Well-Installed Aluminium Fascia Looks Like: Checking the Finished Work
Before accepting the finished work and releasing final payment, it is worth checking the installation meets the standard expected for a quality aluminium roofline.
The boards should run straight and true along the full elevation with no visible bowing or undulation. An irregular substrate under the fascia produces a wavy fascia face, and this should have been corrected at the rafter preparation stage rather than left to be covered.
Expansion gaps of 3 to 4mm should be visible at every joint between board sections, covered neatly by the union trim. A joint with no visible gap is a board that has been fixed without expansion allowance, which will buckle in summer. A visible gap without a trim covering it is an incomplete installation.
Corner pieces should sit flush and tight at every return with no visible gaps at the edges. Gaps at corners allow water to track behind the fascia and will eventually cause staining on the wall behind.
All visible fixings should be stainless steel. If coloured fixing caps have been used to match the fascia colour, check that they are correctly seated and covering the fixing head fully.
The gutter should sit evenly on its brackets along the full run with a consistent gradient toward the outlet. The gutter bracket fixings should pass through the fascia into the structural timber behind. A bracket fixed only into the aluminium fascia face, without reaching the rafter end behind it, will not hold under the weight of a full gutter.
Sealant at joints and corner trims should be neat, smooth, and fully covering the joint face. Sealant that is missing at any point is a leak waiting to happen. Sealant that has been applied badly — lumped, smeared, or visible on the face of the board — should be cleaned up before the job is signed off.
Aluminium Fascia as Part of the Complete Roofline System
The fascia does not function in isolation. It is the connecting element between the roof structure above and the guttering and soffit on either side, and the system works best when all three are specified and installed as a coordinated whole.
The soffit connects to the fascia at the front of the eave. For aluminium soffit boards, the front edge engages with the fascia profile's return lip, producing a clean, continuous enclosed eave. For this to work neatly, the fascia profile needs to include the appropriate receiver detail for the soffit system being used. This is a specification point worth confirming with the supplier before ordering — a fascia and soffit from different manufacturers may not interlock cleanly even if both are aluminium, because the interfacing details differ between systems.
The guttering attaches to gutter brackets screwed through the fascia into the rafter ends behind it. For aluminium gutters in a matching colour, the transition from fascia to gutter is seamless in both material and finish. The full aluminium roofline range at Online Metal Store Ltd includes fascia boards, soffit panels, gutters, downpipes, and all associated accessories in matched powder-coat colours, making it straightforward to source and specify the complete system from a single supplier.
For guidance on specifying the soffit element of the system alongside the fascia, the how to choose aluminium soffits guide covers ventilation requirements, vented versus non-vented specification, and width selection in detail.
Conclusion: Why Aluminium Fascia Is Worth Specifying Properly
Aluminium fascia is not a luxury upgrade. It is the material that solves the problem timber and uPVC create: a roofline element that the building's owner has to keep thinking about. Whether that means repainting every five years, resealing joints every decade, or replacing the whole system every twenty-five years, the timber and uPVC options both guarantee ongoing attention.
Aluminium, specified correctly — 2mm gauge, architectural grade powder coat, marine grade alloy where the environment demands it — installed correctly with stainless fixings, expansion gaps, floating fix at all positions, and low-modulus sealant at joints, does not need that attention. You fit it, colour match it to the rest of the exterior, and you are done for the next four or five decades.
For anyone placing an aluminium fascia order or planning a full roofline upgrade, Online Metal Store Ltd fabricate aluminium fascia boards in any profile, any width, and any RAL colour with standard lead times of three to five working days for stocked colours. Based in Chelmsford, they deliver across the UK and offer specification support for both domestic and commercial projects at every scale.
Frequently Asked Questions About Aluminium Fascia
1. What thickness should aluminium fascia be?
The standard thickness for aluminium fascia board in residential and commercial roofline applications is 2mm. This provides sufficient structural rigidity to support gutter brackets and the loaded weight of a full gutter without flexing, and handles the thermal cycling of the British climate without distorting between fixings. Thinner-gauge product at 1.2mm or 1.5mm is available at lower cost but lacks the same stability and should not be specified where gutter brackets are being fixed directly to the fascia face.
2. Can I use standard screws with aluminium fascia, or do I need specialist fixings?
Stainless steel fixings are required for all aluminium fascia installations. A2 or A4 grade stainless steel screws or nails must be used. Standard mild steel fixings create a galvanic couple with the aluminium that accelerates corrosion at the fixing point, leads to staining, and eventually causes the fixing to fail. Zinc-plated or electroplated steel is slightly better than bare mild steel but still not recommended for aluminium. The cost difference between stainless and standard steel fixings is negligible relative to the installed cost of the system.
3. How is aluminium fascia fixed without buckling in summer?
The key is the floating fix installation method. One fixing per board length is made through a round hole as the dead fix. All other fixings are made through slotted or oversized holes, leaving clearance for the board to expand and contract around the fixing. The dead fix prevents the board from translating along the wall, while the floating fixings allow it to expand and contract symmetrically. Expansion gaps of 3 to 4mm are left at every joint between sections, and the joint trims float over these gaps rather than being rigidly fixed to both sections. Getting this right is what separates an installation that looks perfect in all seasons from one that buckles visibly on a hot summer day.
4. Do I need to paint the cut ends of aluminium fascia on site?
Yes. Whenever an aluminium fascia board is cut on site — for length or for a corner angle — the raw aluminium edge exposed by the cut should be touched up with the matching powder-coat touch-up paint supplied by the manufacturer. The raw aluminium edge is not sealed by the factory powder coat and is vulnerable to surface oxidation, which appears as a white crystalline discolouration over time. Touch-up paint is a minor step that takes a few seconds and makes a visible difference to the long-term appearance of the cut edges. Always cut with the powder-coated face down on the saw table to minimise scratch risk to the finished surface.
5. Can aluminium fascia be fitted over existing timber fascia, or does the timber need to come off first?
Aluminium fascia should not be fitted over existing timber that is rotten, soft, or moisture-damaged. This is the single most important point on this question. The timber is the substrate into which the gutter brackets and fascia fixings will be secured, and a bracket fixed into soft timber will begin pulling loose within months. New aluminium over rotten timber solves the appearance problem temporarily while the structural problem continues to develop behind the boards. The right approach is to remove the existing timber, inspect the rafter ends, treat or replace any damaged timber, and install the aluminium onto a sound, clean substrate. If the existing timber is genuinely in good condition — dry, structurally sound, and free of rot — capping with aluminium is possible, but confirm the condition with a proper inspection before proceeding.
