Roof Info

1.   Roof Shapes

Not all roof shapes are equally suited for loft rooms. To understand which will work best, we first have to understand what the different roof types look like.  The two main and most well–known shapes are the “Gable to Gable” roof and the “Hip to Hip” roof.  Most of the other roof shapes are combinations of these two.

a.   Gable to gable roof

This is the simplest roof shape, but also the most versatile.  It is by far the best shape to use for exposed trusses, as there are no complicated truss systems with many visible hangers and nails. It is also the preferred roof shape for attic roofs, as it maximizes the attic space and creates the opportunity to have big windows in the gable-end walls.

Gable to Gable RoofGable to Gable Framing

 

 

 

 

Gable to Gable Roof and Framing

b.    Hip to hip roof

This roof shape is preferred by many, as they feel it brings a kind of elegance to the roof by breaking the monotonous ridge line of the gable to gable roof. Unfortunately exposed trusses do not go well with hips because of the complicated hip system of trusses with visible hangers, nails etc. in the hip area. Attic trusses also do not go well with hips because of the loss of attic space in the hip area. A new attic roof should preferably be gable to gable. An existing hip to hip roof can be converted to loft rooms, but please be aware of the limited space in the hip area.

Hip to Hip roof

  

 

 

 

 

Hip to Hip Roof and Framing

c.            Dutch hip or Louvre hip

The construction of a Louvre hip is very similar to that of a normal hip roof, but with the difference that a vertical plane is introduced into the hip end, about two-thirds up the hip line.  A triangular louvre is then installed in this opening to aid with roof ventilation. This method extends the horizontal ridge line into your hip area, which creates more living space in your roof hipped roof.   The louvres can be replaced with triangular windows to allow lots of light into the attic room. 

Louvre Hip Framing 

 

 

 

 

Louvre Hip and Louvre Hip Framing

d.            Barn hip / Half hip/ Jerkin hip

The term “hip” in this case is a bit misleading, as the Barn hip is mainly a gable. In the top part (about one third of the total height) a small hip area is introduced.  The Barn hip is thus a gable / hip combination. The Barn hip is similar to the gable to gable roof and can work well with attics or exposed roofs. 

Jerkin Hip

 

 

 

 

 

 Barn Hip and Barn Hip Framing

e.            Parapet Ends

This is a normal gable to gable roof, but with the difference that the roof covering stops at the inside of the gable wall, and the gable wall is built up to about 500mm higher than the roof plane. This method was used in the old days for the typical west coast “Fisherman’s Cottages”. The gables were built up to secure the Blue gum ridge beam and the end parts of the thatch. The top of the parapet was plastered round or tapered to make sure the water runs off the parapet and does not penetrate into the wall. Another good example of parapet walls is the Cape Dutch style gables.

 

 

 

 

 

Parapet Gables  &  Cape Dutch gable at Oude Paarl

 f.            Polynesian Roofs

This type of roof has two pitches – a lower pitch on the bottom part of the roof, and a steeper pitch on the top part of the roof.  (Typical pitches would be 17.5 degrees and 35 degrees.) The Polynesian shape can be used for gable to gable or hip to hip roofs.  The Polynesian hip construction is even more complicated than the standard hip, and this hip area is expensive to design as attic space.

 

 

 

 

 

 

Polynesian Roof - Gable to Gable & Hip to Hip

g.            Gambrel roof

This type of roof also has two pitches, but in this case the lower part of the roof has the steep pitch, and the upper part the shallow pitch.  It is designed to maximize attic roof space. Gambrel roofs are popular in the USA and England as roofs for farm sheds with lots of storage space in the top area.

 

 

 

 

 

 Gambrel Roof and Gambrel Truss

h.            Mansard Roof

This is a Gambrel roof with hipped ends (and in my opinion not the most elegantly looking roof available).  It is also not the most structurally stable roof, and provision must be made for internal support points below the truss to make sure that a lot of space is not lost to truss-strengthening areas.

 

 

 

 

 

 

Mansard Roof