Types of Roof

Types of Roof

Your roof was originally designed and constructed to protect you from the elements with an allowance for additional loads from general loft storage. Converting your loft means calculations will need to be made for the new structure. New timber rafters and suspended floor structure will need to be designed by our Architectural Technologist/Structural Engineer. Depending on the type of roof construction of your loft will effect the new design. There are generally two types of roof.

Modern trussed roof design

The modern truss roof design can be found in almost all newly built houses. These houses are usually built with no load bearing walls on the interior of the 1st floor. The new timber suspended floor may need to be supported on the perimeter walls. RSJ’s (Rolled Steel Joist) are almost always inserted to accommodate the long spans supporting the new floor. Roof trusses are complex and precisely calculated pieces of structural engineering. Removing any section during your loft conversion should be carried out by an expert. If not carried out correctly structural damage to your roof and walls can happen.

Minimum dimension necessary for a loft conversion– measure from ceiling to very top of the adjoining rafters- 2.500 metres. Our Architectural surveyor will measure the height during the survey.

An example of a modern truss roof can be viewed on Previous Projects Case Study 7 Loft Conversion.

PLEASE NOTE:- If your roof is not high enough then a dropped landing or lowering the ceilings should be considered.

Pre 1960”s traditional cut & pitched roof design.

Pre 1960’s traditional cut and pitched roof designs are normally found in older style houses and are easier lofts to convert. They do not require as much height as a modern trussed roof but just like a modern truss roof will need structural calculations for a loft conversion. Unlike the modern truss roof load bearing walls are usually present on the 1st floor which are used to support the new floor joists.  

An example of a traditional cut and pitched roof can be viewed on Previous Projects Case Study 3 Loft Conversion.

For minimum dimension necessary for a loft conversion– measure from ceiling to the bottom of ridge board- 2.400 metres. Our Architectural surveyor will measure the height during the survey.

PLEASE NOTE:- If your roof is not high enough then a dropped landing or lowering the ceilings should be considered.

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