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300mm Lead Flashing – Code 4 & Code 5 Lead Rolls for Roofing
300mm Lead Flashing – Code 4 & Code 5 Lead Rolls for Roofing
300mm lead flashing is one of the most useful wider lead sheet formats for chimney aprons, deeper cover flashings, roof abutments, back gutters and substantial weathering details. It gives considerably more material to work with than narrower 150mm, 180mm or 210mm lead rolls, making it especially useful where greater cover, deeper upstands or more complex dressing is required.
At The Lead Shop by The Lead Lads, we supply 300mm lead flashing in practical rolled lead sheet formats, particularly Code 4 and Code 5. This guide explains which code to choose, how much 300mm lead weighs in 3m and 6m rolls, where the width is most useful and when a different size may be more appropriate.
What is 300mm lead flashing used for?
The main advantage of 300mm lead flashing is the additional width available for forming deeper or broader weathering details. It gives installers more scope for achieving adequate cover over roof coverings while still allowing sufficient upstand, lap or return into the adjoining construction.
Typical uses include:
- chimney aprons
- larger stepped and cover flashings
- deep wall abutments
- rooflight and dormer details
- back gutters and formed junctions
- wider tile and slate weatherings
- parapet and cornice details
- repairs where existing lead requires substantial cover
Code 4 or Code 5 for 300mm lead flashing?
The two most useful starting points for 300mm lead flashing are generally Code 4 and Code 5. The correct choice depends on exposure, detail type, required stiffness and overall design.
| Lead code | Approx. thickness | Approx. mass | Typical 300mm use |
|---|---|---|---|
| Code 4 | 1.80mm | 20.41kg/m² | General exposed flashings, chimney work, deeper cover flashings and wall abutments |
| Code 5 | 2.24mm | 25.40kg/m² | Heavier aprons, more exposed weatherings, substantial junctions and wider formed details |
Code 4 300mm lead flashing is often the more economical and workable option for routine exposed flashing work. Code 5 300mm lead flashing adds greater thickness and rigidity where the detail is more demanding.
How much does 300mm lead flashing weigh?
Because 300mm lead flashing is wider than many everyday flashing rolls, its weight becomes commercially and practically important. The roll length and code both have a significant effect.
| Specification | Area | Approx. weight |
|---|---|---|
| Code 4 – 300mm × 3m | 0.90m² | Approx. 18.4kg |
| Code 4 – 300mm × 6m | 1.80m² | Approx. 36.7kg |
| Code 5 – 300mm × 3m | 0.90m² | Approx. 22.9kg |
| Code 5 – 300mm × 6m | 1.80m² | Approx. 45.7kg |
These figures are useful for planning delivery, lifting and transport. They also help buyers understand why wider Code 5 rolls quickly become substantially heavier than equivalent Code 4 products.
For other combinations, use the Lead Weight Calculator to calculate approximate roll weight instantly.
300mm lead flashing in 3m rolls
A 300mm lead flashing 3m roll is often the best choice for repairs, chimney work and medium-sized roofing projects. The 3m format provides useful material without creating the handling challenges associated with longer, heavier rolls.
- easier to lift and transport
- practical for domestic scaffold access
- useful for one-off chimney and abutment jobs
- lower individual roll weight
- good control over cutting and offcuts
For Code 5 in particular, the 3m format is often attractive because it keeps a 300mm-wide roll at a manageable weight of roughly 22.9kg before packaging.
300mm lead flashing in 6m rolls
A 300mm lead flashing 6m roll is better suited to contractors using the same width repeatedly across larger projects. It gives twice the material of a 3m roll and can be efficient when multiple aprons, cover flashings or other formed pieces need to be cut.
The main trade-off is weight. A 300mm Code 4 6m roll weighs around 36.7kg, while Code 5 at the same size is approximately 45.7kg. That means handling should be considered before ordering.
300mm lead flashing for chimney aprons
One of the strongest uses for 300mm lead flashing is forming chimney aprons. The additional width allows the installer to create a suitable upstand behind the masonry flashing while still providing enough material to dress over the roof covering.
The exact dimensions required depend on the pitch, roof covering and chimney geometry, but 300mm is often a highly useful stock width because it offers greater flexibility than narrower rolls without immediately moving into very wide sheet.
300mm lead flashing for stepped and cover flashings
For deeper stepped flashings and wall abutments, 300mm lead flashing can provide additional cover where narrower 150mm, 180mm or 210mm rolls would leave too little material for the required upstand and roof coverage.
This can be especially relevant with profiled tiles, irregular masonry or roof details where the lead needs to bridge a greater vertical or horizontal distance.
300mm lead flashing and profiled roof tiles
Wider flashing becomes particularly useful over more pronounced tile profiles. Pantiles, deeply profiled concrete tiles and other shaped roof coverings can demand greater material width because the lead must be dressed over the contours while still maintaining adequate coverage.
In these situations, Code 4 or Code 5 may be selected depending on the precise geometry and exposure of the roof.
When is 300mm lead flashing too wide?
Wider is not automatically better. If a simple cover flashing can be formed correctly from 150mm or 210mm sheet, buying 300mm lead may simply increase material cost, weight and waste.
A narrower roll may be more appropriate where:
- the masonry chase is shallow
- the roof covering needs only modest overlap
- the flashing is small and straightforward
- the wider material would need excessive trimming
- the added lead weight offers no design benefit
When is 300mm lead flashing too narrow?
Equally, there are circumstances where 300mm does not provide enough material. Larger aprons, back gutters, wide roof junctions, parapet details and broad weatherings may require 360mm, 450mm, 600mm or much wider rolled lead sheet.
For these jobs, start with the Lead Chart rather than forcing a 300mm roll into a detail that genuinely requires more width.
300mm Code 4 lead flashing
300mm Code 4 lead flashing combines a useful wider format with the most familiar general-purpose exposed flashing code. At approximately 1.80mm thick, it can be dressed relatively easily while providing a more substantial weathering than narrower lead rolls.
It is particularly relevant for:
- chimney apron flashings
- larger stepped flashings
- deep wall abutments
- general roof penetration detailing
- wider cover flashing requirements
300mm Code 5 lead flashing
300mm Code 5 lead flashing is heavier and stiffer than Code 4. At approximately 2.24mm thick, it is often appropriate where a wider flashing needs more substance, or where the same 300mm width is being used to form more demanding weathering details.
Typical applications can include:
- substantial chimney aprons
- back gutter details
- wider exposed weatherings
- parapet junctions
- more demanding refurbishment or heritage details
Can 300mm lead be used for soakers?
It can be cut into soakers, but 300mm lead flashing is often wider than required for normal concealed soaker work. Standard soakers are commonly formed from Code 3 lead in narrower widths such as 180mm or 210mm, depending on the slate size and required upstand.
Using 300mm solely for small soakers may create unnecessary waste unless the geometry of the roof genuinely requires the additional material.
For more detail, see our guide to Lead Soakers.
BS EN 12588 and 300mm rolled lead sheet
The lead code and dimensions should be considered alongside material quality. Rolled lead sheet should be manufactured to BS EN 12588, which defines rolled lead sheet specifications and helps ensure consistency in thickness and weight.
Installation should also follow recognised leadwork guidance, including suitable piece lengths, movement allowance, laps and compatible fixing methods.
Good practice when installing 300mm lead flashing
- Confirm the width actually provides the required cover and upstand.
- Do not over-fix exposed lead.
- Allow for thermal expansion and contraction.
- Use correct laps for roof pitch and exposure.
- Use copper or stainless fixings where appropriate.
- Secure chases with suitable lead clips or wedges.
- Use patination oil on freshly installed exposed lead where appropriate.
- Keep individual pieces within sensible lengths for the detail.
What should I order with 300mm lead flashing?
Depending on the work, the lead itself may be only one part of the complete order.
- Leadwork Fixings
- Hall Clips
- Lead Mate Sealant
- Lead Patination Oil
- Lead Underlay for suitable supported weatherings
How much does 300mm lead flashing cost?
The cost of 300mm lead flashing depends on the code, roll length and current material pricing. Code 5 will cost more than Code 4 for the same width and length because it contains more lead per square metre.
If you are comparing lead commercially, it is useful to understand the price of lead per kg as well as the finished roll price. This helps explain why code and roll weight have such a strong effect on the final product cost.
Buy 300mm lead flashing online
The quickest way to select and buy 300mm lead flashing is through our Shoppable Lead Chart. Choose the lead code and roll format you need, compare the available options and move directly into the relevant product.
If you are unsure about handling weight, check your selected format using the Lead Weight Calculator before ordering.
Frequently asked questions – 300mm Lead Flashing
What is 300mm lead flashing normally used for?
It is commonly used for chimney aprons, deeper cover flashings, substantial abutments, roof penetration details and other junctions requiring more width than standard narrow flashing rolls.
Should I choose Code 4 or Code 5 in 300mm width?
Code 4 is a strong starting point for many standard exposed flashing applications. Code 5 may be more appropriate where extra rigidity, durability or more demanding weathering performance is required.
How heavy is a 300mm Code 4 3m roll?
A 300mm × 3m Code 4 roll has an area of 0.9m² and weighs approximately 18.4kg before packaging.
How heavy is a 300mm Code 5 6m roll?
A 300mm × 6m Code 5 roll has an area of 1.8m² and weighs approximately 45.7kg before packaging.
Is 300mm lead suitable for chimney flashings?
Yes. 300mm is a useful width for many chimney apron, cover flashing and deeper abutment details where narrower lead would not provide enough cover.
Can I buy 300mm lead flashing in 3m and 6m rolls?
Yes, depending on the code and stock range. Three metre rolls are usually easier to handle, while six metre rolls can be more efficient for repeat trade usage.
Is 300mm lead flashing too wide for normal stepped flashings?
It can be. Many straightforward stepped flashing details can be formed from narrower widths. The correct width should be based on actual upstand, cover and roof geometry rather than simply choosing the widest available roll.
