For centuries Lead sheet has been the standard for roof coverings of many of Britains most prestigious and important buildings. When correctly detailed lead will outlast all other commonly used roofing materials by many years. Whether lead is used as the main roofing material or as a gutter lining or flashing, properly installed Lead is unsurpassed in it's durability and longevity.

OFFICE 01373-825573 MOBILE 07836-692-394

Please see our artical regarding LEAD THEFT.

We will undertake repairs or renewal of lead valleys, lead gulleys, stepflashings, lead roofs including mop roll details etc. In fact we can undertake any type of lead works that may be required.

We will be adding many photos of completed lead contracts to our portfolio shortly.

Physical and Mechanical Properties of Lead Sheet
Malleability - Lead is soft, malleable and capable of being manipulated with hand tools and, by the technique of bossing, can be worked into the most complicated of shapes or dressed to fit the many types of profiled roofing tiles.

Fatigue and Creep Resistance - Attention to correct sizing and fixing of individual pieces minimizes any risk of fatigue cracking or creep. The chemical composition of rolled lead sheet is strictly governed by the provisions of BSEN 12588:1999, which effectively control the grain structure to make the lead sheet more resistant to thermal fatigue without affecting malleability.

Durability and Thickness - When specified and fitted correctly, rolled lead sheet can continue to provide a maintenance free weather shield for 100 years. Rolled lead sheet is therefore extremely resistant to atmospheric corrosion. The ideal thickness and size of each piece is determined by the application. Thicker sheets may be required :

When dressing lead into deeply profiled tiles

In areas of frequent foot traffic

On flat roofs and gutters

Where extra rigidity is required to resist wind uplift

Thermal Movement - Lead sheet has a high coefficient of linear expansion and therefore due allowance for thermal movement must be made in the design, layout, sizing of panels and fixing details to maximize performance.

Fire Resistance - Lead is incombustible but melts at 327.4C.

Recyclability - Rolled lead sheet is totally recyclable. Scrap material is recovered from end of life buildings in the UK by a national network of reclamation merchants and channelled back to the manufacturers where it is carefully refined back to new feedstock for the rolling mills. The established recovery network, constant recycling of old material and low melting point with resultant energy efficiencies in manufacturing means the lead sheet industry has a solid reputation for environmental awareness and as a conserver of natural and energy resources.


Contact with Other Materials

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Rolled lead sheet works in harmonious partnership with most building materials, however additional precautions may be required when using some types of materials to avoid any deleterious effect on lead sheet particularly in the presence of moisture.
It is important to check for compatibility when specifying or using certain types of the following materials:-

Timber
Underlay
Sealant
Adhesive
Concrete and Mortar
Other Metals


Bossing and Welding Methods

Lead sheet should be carefully worked or welded so that the lead is not thinned by more than 25% or weakened by creasing or stretching. Bossing and welding lead should be carried out by experienced (preferably registered) operatives using the proper tools and equipment.

It is important to check for compatibility when specifying or using certain types of the following materials:-


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Jointing Methods
Joints in leadwork are weathertight but not watertight. Joints in leadwork are designed to keep water out whilst allowing for thermal movement. It is therefore important that the type of joint used is appropriate for the type of application or situation.


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Support and Fixing Methods

Lead sheet must be adequately supported on a smooth base sufficient to take the weight and to allow for thermal movement to take place. It may be laid on timber, plywood, concrete or masonry together with a suitable underlay. The lead sheet should be held in position with fixings of a type, strength and position which:

Support the weight of the lead sheet
Are resistant to corrosion
Allow for thermal movement to take place
Resist wind uplift

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Preventing Corrosion

Lead sheet is resistant to most forms of corrosion likely to be encountered in a roofing situation, but certain precautions need to be taken against the following:
Mortar: Unprotected lead damp proof courses and cavity trays may corrode in the presence of moisture
Lichen Growth: The acid run-off from lichen or moss on a roof may cause small holes to appear in the lead sheet under the drip-off point from tiles or slates. A sacrificial flashing may be fitted to the lead gutter or roof, or the growth may be treated with a chemical fungicide.
Condensation: In certain conditions the underside of lead sheet may corrode and it is important to design the roof to reduce the risk of condensation and provide adequate ventilation.


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LEAD SHEET (MILLED)

Lead sheet has been produced by rolling since the mid 1700's and by the turn of this Century, rolled (milled) lead sheet was being used in the UK as an alternative to sand cast sheet for roofing and weathering.

Rolled lead sheet is formed by passing a slab of refined lead back and forth on a rolling mill between closing rollers, (nowadays often computer controlled) to a predetermined thickness. The sheet is then slit to width and cut to length for final packing and distribution.

Such is the consistency of the process that rolled sheet will not vary in thickness by more than +/- 5% at any given point.

Rolled lead sheet is the only type which is manufactured to a British and European Standard.

BSEN 12588:1999 specifies thickness tolerances and chemical composition in order to produce a consistent microstructure. The minimal variance in thickness means when fitted to a roof, the extent of thermal movement can be accurately predicted and the correct fixing method adopted.

The technical advice and literature of the Lead Sheet Association is based solely upon the use of rolled lead sheet to BSEN 12588:1999 and the design and construction of fully supported lead sheet roof and wall coverings (BS6915:2000).



Sand Cast Sheet

The Romans first used sand cast sheet for water ducts and storage tanks. Its use was extended by the Normans to include roofing applications. Many church and cathedral roofs originally used sand cast sheet and records show the material has an outstanding lifespan when fitted correctly.

Today, the traditional method of manufacture persists, with molten lead being poured across a prepared bed of sand and then "skimmed" to the required thickness. The material is mostly hand-produced by a small number of specialist companies, providing sand cast sheet primarily for its rough grain aesthetic appearance or where there is a requirement on an historic property to replace "as existing".

Its past performance record is generally due to the overall thickness and weight of the sheet used, with a 12" (305mm) square traditionally weighing 6 - 8lbs (2.7 - 3.6kg).

Sand cast sheet is not produced to any fixed chemical composition, it is not made to any British and European Standard, it does not have an Agrement Certificate.

Machine Cast Sheet

Machine cast or DM (Direct Method) lead sheet was developed as a building material in the mid 1950's in Australia and introduced as such in the UK in the 1980's.

It should not be confused with either rolled sheet or traditional sand cast sheet.

Produced by immersing a rotating water cooled metal drum into a bath of molten lead, the lead solidifies on the surface of the drum and is lifted from the molten bath and is peeled away as the drum rotates. The thickness of the sheet thus produced is determined by the speed of the drum rotation, the depth of the immersion and the temperature variation between drum and bath.

Machine cast sheet differs from rolled and sand cast sheet in both surface finish and grain structure. The surface of the finished sheet not in contact with the drum has a dimpled finish whilst the other side is comparatively smooth.

Machine cast sheet is not made to a British and European Standard and cannot be consistently produced in the UK to the thickness tolerances achieved by rolled sheet. Individual DM manufacturers in the UK have obtained their own British Board of Agrement Certificates but these only detail the chemical, physical and technical characteristics of each manufacturer's own product.

Why is lead so becoming a target for theft.

It's all to do with the industrialisation and urbanisation of china. The eastern giant, with a population of 1.3 billion, is going through its own Industrial Revolution and one on a massive scale, china's cities are growing at such a rate that by 2020 an extra 400 million people will have been urbanised.

That means that over the next 15 years ,something like 20 million people will be urbanised every year ,that's like building new York and London every year.

The result was that china is" mopping up" the worlds reserves of metal. the past three years or so metal has more than doubled. lead is now thought to fetch

A £1,000 a tonne-while copper is now fetching £3,500 a tonne, no wonder the criminal world is taking notice.

WHO ARE THE THIEVES TARGETING?

Schools, churches , shops, factories, railway lines, care homes, residential homes, if they can take it ,they will .churches and schools seem to be the most at risk as they are often isolated, and have high level of lead and copper on their roofs

How can we help you protect your home, we can supply and apply selecta dna grease, Police have immediate evidence that the lead thief has been up to no good. Police can then forensically analyse the perpetrator and the stolen lead and link the suspect to the crime scene. Protect your home, school or church today with SELECTADNA Grease. The Grease with a secret DNA tracer allows you to mark lead windows, lead pipes and lead roofing quickly and easily. Then putting up bright orange warning signs that everything is DNA marked, warns lead thieves to stay away.

HOW MUCH DOES IT COST?

S.F. Roofing will charge at cost for this protection, but please bear in mind its not just the stolen lead replacement value to consider it is also the cost of any internal damage due to water ingresss etc.