The gambrel roof is also known as barn roof. We are looking at quite a simple gable love that also has a slope partway slope right on the roof. The appearance is unique and attic floor space is maximized. However, building such a roof type is a little complicated.
Different Gambrel Types
We basically have two types of gambrel roofs: regular and custom. One that is regular will fit perfectly in a semi-circle that is circumscribed. We have fixed slopes of 28 31/32 over twelve in the low rafters with 4 31/32 over twelve in upper rafters. All face or side will be of equal length. As a lower span gets changed, all dimensions are modified, recalculated in order to maintain proportions. The custom gambrel roofs are 100% flexible and there are no real restraints in sizes.
Gambrel Roof Framing Methods
We normally have 3 different framing options available when referring to joining lower and upper roofs. The first one is the Purlin method. In this case we have bottom and top cuts calculated in order to bisect angles at roof joints with ridges levels. Purlin boards are utilized between them.
The second one is the Flush method, also referred to as wall supported method. Upper rafters will be placed on walls with lower rafters being butted on wall studs. The third one is the Raised method, also known as wall supported. Upper rafters are raised so that square cut fascia lines are created at roof break.
Calculating Gambrel Roof Sizes
While there are different formulas and calculations that you can easily make in order to see exactly what the size of every single element is, the truth is that it is quite complicated and you need a lot of math. The great news is that you can easily avoid having to calculate roof sizes by simply using an online gambrel roof calculator. The one from Block Layer is pretty straight to the point. You can calculate everything based on requirements you may have. The truth is that a regular gambrel roof is usually preferred but the custom one is also going to be great in the event that you need a specific storage area in the attic.
