Calculate The Rooftop Height

The key to the success of any undertaking is the correct calculation, and this also applies to the construction of the roof. How to calculate the height of the roof and what most often affects its height, how to properly plan the attic, and find out how the ridge differs from the rafter – all this is considered further.

What is a roof and what does it consist of?

The roof is the main element of any building. Its direct purpose is protection from atmospheric precipitation and exposure to direct sunlight in summer and from cold in winter. But, in addition to a purely practical purpose, it also carries an aesthetic function. 

This structural element of the house can be seen from afar, the owners are judged from its appearance, and various design solutions add originality and uniqueness to the residential building.

The online square footage calculator will help you in the measurement of the residential building.

There are three main types of roofs:

• single-slope;
• gable
• four-slope.

The slope intercept calculator will help you calculate the slope, elevation, or distance at the right time without any problems.

The most popular of these three types is the gable, a classic building that looks like an upside-down open book. Houses with such a roof can be found in almost any cottage village; this is exactly what is being built over garages and outbuildings.

The central structural element of the roof is the rafters. These are inclined beams that take on the main road. Two rafters connected together form a triangle structure. Several such triangles, placed one behind the other and connected by lags, make up the roof frame. Insulation and roofing material are laid on such a frame.

The rafters themselves are attached below to a special beam – Mauerlat. The main method of fastening, in which the angle of inclination of the slope is maintained, is cutting the rafters by approximately 1/3 of its thickness and securing it with brackets, bolts, tightening beams, and the like on the Mauerlat.

Roof structural elements

Two-end “triangles” are usually called pediments. Such a separation from the general series is quite understandable – these pairs of connected rafters are visible from the outside and increased requirements are imposed on their appearance.

The lower part of the rafters, extending beyond the box of the house, forms a cornice, which does not allow rain puddles and piles of snow to accumulate right against the wall but carries them out to some distance.

The rib at the junction of two inclined surfaces is called a ridge, and the horizontal beam itself, on which the rafter legs rest, is called a ridge beam or a bridge girder.

What determines the height of the roof?

Calculation of the height of the roof is reduced to finding the optimal angle of inclination of its constituent planes. This figure is influenced by several factors, each of which either increases or decreases the height of the canopy. Let’s consider each of them separately.

Precipitation

Here it is rather customary to talk not about rain because liquid water flows from the surface with any angle of inclination, but about snow, or rather snow load. The fact is that the masses of snow accumulated over the winter on the roof weigh a lot and add additional load on the supporting structures of the roof. 

Therefore, it is best that the snow does not linger on the roof, but falls to the ground by gravity. This is all the more important in those regions where there is significant snowfall. For such areas, the optimal roof slope angle is at least 45°.

Wind load

A strong gusty wind that prevails on the terrain requires that the roof be, on the contrary, more sloping and shallow, no more than 20 ° to the horizon. This is because a high roof increases its windage. 

Air masses press on such a roof, and therefore on the supporting structures, more strongly, all elements are under increased stress. The gusty wind is most dangerous. He strives to tear the roof off, destroy the roof.

Roofing material

The smaller the roofing element, the higher the roof it requires for itself. This is quite understandable: a small tile has many more lines for snow to catch on, and, accordingly, a snowcap grows. 

Therefore, for such a roof, a larger angle of inclination is best. In fact, the most optimal roof slope is indicated on the packaging of any roofing material. So there are no definite trends here.

Increasing the roof height also increases the load on the supporting structures. At the same time, the area of ​​the roof itself also grows, which entails an increase in the cost of roofing material, rafters, and frame elements designed to strengthen the entire structure.

Attic

Before calculating the height of the gable roof ridge. It is necessary to determine exactly how the space under the roof will be used. Most often, outbuildings and garages do not have a ceiling, and when entering such a building, you can see the rafters and supporting elements of the canopy.

However, in residential buildings, most often the top of the rooms is separated from the under-roof space by an overlap, which is also the floor for the attic.

An example of arranging an attic

You can use the resulting room under the roof in two ways: 

1. as non-residential (usually as a warehouse) or 
2. as residential. 

In any case, such premises have their own special requirements:

Even a non-residential attic requires periodic maintenance.

And when using it as a storage place for various inventory, the homeowner may need to climb into the attic. In this case, there must be a passage under the roof at least 160 cm high and 120 cm wide.

If the roof has a complex shape and it is not possible to provide such dimensions of the passage, then its height and width can be reduced by 40 cm.

The dwelling attic assumes that people will always be here.

Such rooms are constructed in two tiers when the higher lower one is separated from the small upper part by a kind of ceiling. In any case, the height is adjusted according to the tallest owner of the house.

It is necessary to add 40 cm to this value. So that family members are as comfortable and convenient as possible to move around the attic. As a rule, the total height of a residential attic is 2.20 – 2.30 m.