Adding a space onto an existing home is probably the most cost effective way to increase a building’s functional interior space. In this article, an addition means exactly what an associate calls a “3 sided” addition. This phrase intends to avoid confusion with other sorts of house additions such as raising a building to create a new ground level area, or raising the roof to create a story between a ground level area and a roof area. The three sided addition means that the new and existing building will share an interior wall.
The very first factor to consider when planning an addition is headroom: the height of a ceiling relative to human percentages. Most building codes stipulate minimum ceiling heights, but, as many people prefer ceilings that are at least eight feet (2. 5 m) high, a well-designed area will most likely satisfy or go beyond these. Making sure adequate headroom is probably the most challenging element of addition style, and is the main need to begin planning an addition from the roof down.
Start your style thinking by aiming to envision exactly what you consider a perfect ceiling height for your addition when finished. As mentioned, most prefer a minimum eight feet, but a couple of inches less than this will still work in a pinch. It is important to start here, because your brand-new ceiling will likely be hanging from the roof framing that will, in turn, connect to the existing building. If this framing connects to an existing structure too low, your ceiling will be too low. Let’s look at a couple basic roof frame methods to help clarify.
Gable Dormer: When most kids in the western world draw a house, it will have a gable roof. A gable roof is an upside-down “V.” A gable dormer is this same roof shape connected to an existing main building at a right angle. It will have a peak as does the children’s drawing, and where its roof meets the primary roof is called a valley. As people have been utilizing gable dormers for centuries, you won’t have to look far for an example. The primary advantage to a gable dormer when developing an addition is that the addition’s ceiling height is determined by how high its peak is relative to the main structure. Generally, the higher the peak, the greater the offered ceiling height.
As with any structure job, there is apparently no end to advantages and disadvantages, and compromises require be discovered. When utilizing a gable dormer frame for an addition, the compromise is that much of its weight will bear on the existing or main roof framing due to the fact that it overlaps this framing. As the primary roof framing was not likely designed to support this additional weight, this primary roof frame will need to be strengthened. Obviously, there are a few more in and outs to know about putting a lid on your addition using the gable dormer approach, however in my viewpoint, this method is the slickest, and in the long term, will offer much better looks than many alternatives. Due to the structural reinforcing, and other framing elements required when using a gable dormer, it will likely cost more, also.
If thinking about the gable dormer method, one thing to bear in mind is that because a substantial addition’s roof dormer will cover a significant part of the existing roof, hold back on re-roofing till the dormer is in location. This will save burying a great deal of brand-new roofing product under the new dormer.
Shed Roof: The shed roof or shed dormer has an unfortunate name, but when artfully developed, shows a cost effective roof frame for an addition, as well as an appealing one. Beginning once again with that inverted “V,” the shed-style addition roof is a flat plane say the shape of a flooring tile or square cracker that satisfies one “leg” of the upside-down “V” someplace. “Somewhere” is the personnel word because this versatile addition roof design can, when well supported, be attached anywhere on a building from the primary roof to its outside wall. In the meantime, let’s suppose the shed roof attaches at the base of the inverted “V.” Ideally, the roof joists your ceiling is hung from will “land” on the outside wall plates where the primary roof frame rests. This makes for simpler framing.
But here’s the difficult part of utilizing the shed-style. Unlike the gable technique which has its drainage slopes constructed into the design, that tile shaped shed roof airplane has to be slanted down, at least a little bit. Just how much depends upon roofing knowledge and the materials chosen. Utilizing the so-called 1: 12 ratio which i think of as minimum, for each foot the roof extends from the main building, the plane, that tile or cracker, tilts down one inch. The difficult part is that at this ratio, every foot far from the main structure is one less inch of headroom. If the addition roof extends 12 feet (4 m) from the main structure, an eight-foot-high ceiling becomes seven with the loss of an inch every foot. This implies that landing your brand-new addition roof on the existing outside wall frame might not supply enough headroom, even when using the minimum 1: 12 pitch ratio. Try this simple formula utilizing a 2: 12 pitch ratio to see why a minimum slope is typically used. Losing two inches of headroom per foot leads to the loss of two feet (60 cm) of headroom over 12 feet.
With headroom in mind, you’re most likely asking, “Can I raise the ceiling to obtain more headroom?” Yes, but you will simultaneously be determining where your new shed roof airplane meets existing work. If that cracker or tile airplane lands too far up the inverted “V” of the primary roof, it will put weight on existing roof framing not planned to support it. This scenario, as with gable dormers, will require some engineering thinking and doing, but in my viewpoint, will deserve the problem. Shed roofs just look much better when they link to a primary roof, rather than being hung from an exterior wall under the eave.
Another excellent way to increase headroom is by decreasing the addition’s floor elevation. This is more commonly essential with single story structures, but can be a difficulty even with a 2nd story addition. The problem is, obviously, that by the time that shed roof is extended far from the structure and headroom is lost based on the formula, the ceiling is so low as to be impractical. In this occasion, about the only alternative available is to “sink” the addition a step or two down to make sure adequate headroom.
A main benefit of the shed roof is its simpleness. It does not demand advanced woodworking abilities to carry out as far as roof framing goes. Instead shed-style addition roofs are challenging because they not only require greater idea about drain and roofing products, but ask also for factor to consider of how structure loads are transferred to their structures, as these are often less obvious than with gable-style additions. A last essential note about utilizing a minimal or “low-slope” roof is not just that a low-slope roof product must be utilized, but extra care is had to guarantee the addition’s roof membrane works out up and under the main building’s roofing product. In general, the lower the slope, the higher this under-flashing.
As constantly, it’s much better when planning a building job to make errors on paper instead of on the job. This thinking is particularly true in additions, where certain components of a plan are pre-determined by an existing structure that may be pricey to modify significantly. Obviously, it’s also real that will usually finds a way, so with a little “top down” considering addition roofs and some fundamental tools, a structure’s usable interior space can be significantly increased without mowing a constructing down and starting from scratch.
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