Why conservation glass

Cylinder Glass includes natural light distortion and is handmade. It was used across Europe between around 1690 and the 1860s and it is from an aesthetic standpoint the optimal glass to use in historically important properties. Listed Planning Officers and Conservation officers normally recommend this for period properties and the glass is made using the same process and the glazing will fit into the historically important rebates in existing windows ( leaded and wood).

Cylinder glass typically does not have a good U value and is not good for heat retention. A 3mm piece of normal cylinder glass would typically have a u value of around 6 to 7 compared to modern double glazing which is 2.8. With our Conservation Glass we can get the U value down to 3.7 for cylinder glass with a rebate thickness of 4mm.

Light characteristics

Transmittance: 0.91
External reflection: 0.08
Absorption: 0.01

Global solar factor

Solar factor: 0.88
(Climatic conditions: specific)

Glazing U-Value

Glazing U-Value: 5.75 (W/m^2k)
(without shading system)

Our Services

Planning Glazing reports

We assess the historic value and importance of every pane of glazing in a building and provide the detailed reports to enable planning and heritage officers to agree to changes to glazing in Listed Buildings.

As part of this service we can also advise on how any historically important existing glazing can be retained and the u value improved to enable significantly reduced heating bills.

Enhanced Historic glazing

Sometimes it is not possible or desirable to replace all glazing in historic properties. Where there is historically important glazing we provide a service to significantly improve the U value of the existing glass in situ which is fully reversible and does no damage to the historic glass.

Conservation Glass

We supply market leading conservation glass with a variety of depths from 2.5mm/3mm to 6mm/6.5mm to fit different glazing rebates. This glass is specifically designed for historic listed 18th and 19th century buildings.

The glass is made from historically accurate cylinder glass . Therefore replicating the original period glass and giving the correct look and tone for your historic property.

Our conservation glass has a special filter which enables an enhanced U value and allows significantly better heat retention for the building - with lower u values than other glass of similar depth on the market.

The unique thin section of the glass allows it to sit readily into the historic sash/period windows without affecting the rebate or the potential weight problem of heavier glass in the window.

Our history

The glass is made from historically accurate cylinder glass. Therefore replicating the original period glass and giving the correct look and tone for your historic property.

In some cases the local planning conservation officer may ask for the age of the glass in order to grant listed building consent for the the new period cylinder glass.

Over the last several years we have been developing both the technology and skills to carry out detailed window glazing surveys and analysis necessary to provide detailed historic window and glazing reports to Listed Planning Officers and English Heritage. These reports then allow clients to both upgrade and reduce the U value of existing historic glazing and where appropriate for historic cylinder glazing to be installed with outstanding U values to significantly reduce heat loss through glazing.

About Conservation Glass