Roof truss spacing

Roof Truss Spacing – The most important thing to note about roof truss spacing is that it is highly dependent on local building codes. This article will help you to know all the factors that will go into what could affect your roof truss spacing.

The Weather. Determining the correct roof truss spacing, as well as the correct materials and how to build your roof trusses, will be largely, if not completely, dependent on the weather that you can expect to receive in your part of the world.

When it comes to standard roof truss spacing, you have to remember that the local authorities will have a better idea of the regulations for that particular area on the conditions in which the roofs in perhaps every area have to operate under than the general advice that you might find online.

If you get the wrong spacing for your roof trusses, and you build a roof that is not built to withstand the pressures of the weather environment of your local area, then the roof can cave in on itself.

So, it pays to contact the local authorities and find out what are the implications of either building or reinforcing your roof. And it pays to see an expert or an architect who can ensure that your design, and later your physical roof, is a specification in regards to the weather.

Things to consider are the fact that you might have snow or ice that will impact on the weight of your roof, you will have rainfall which will mean that you have to design drainage solutions, and you will also need to take into account the wind.

We thought about these things later in the article, and so we will leave that there for now and return to it later.

The width of the building. This is very important to determine because when it comes to building structures, the engineering and the design has to be spot on.

If you are just a few millimeters out, then your groove trusses  can be under immense pressure if the building is either too wide or too narrow. This is because in the design process you need to have the apex of the roof at the highest point in the middle.

Therefore, it only makes sense that the roof trusses have to be specifically measured so that they support the roof at exactly the right point.

You need to know the width of the building, because the width of the building will determine the surface area of your roof. Obviously, a wider building will require more trusses than a very narrow building.


The material that is used to make the roofing. Also because the material that you use to build the roof will it affect how thick the material for the roof truss’s needs to be, and it will also affect how many of them you need within a certain space.

If you are holding according to regulations in which you have to build an old-fashioned style for instance, you might need to use a heavy slate or other stone-based materials.

This is going to be very heavy, and so you do need the trusses to be closer together and capable of supporting more weight.

If you are using metal, depending on what the metal is, this can be either heavy or very light. For instance, aluminum is a very light material for you to build a roof with, it is commonly used in mobile homes and caravans; this means that you be able to get away with more space between your trusses.

Alternatively, you could have something different entirely, such as a thatched roof or other material which is organic material.

There will be a lot of different pressures that act upon this different times over the course of the life of the roof, and so you need to have trusses that will support your roof through thick and thin.

There are also three things that will affect roof truss spacing:

  1. Dead weight load. The dead weight load of a roof is all the different structural elements which can affect the amount of pressure that can be placed on each roof truss. For instance, the material is used in roofing might be  slate, and that will mean that the roof trusses are built with different spacing and different material than, for instance the material and how far to space roof trusses if you had, say, an aluminum roof.
  2. Live weight load. The live weight load of a roof basically comes down to the pressure that it is put on it during a live situation-this can be anything from rain water, (with a is very important that your engineer, or yourself, accounts for this and provides certain drainage solutions that work,) to snow and accumulated debris.
    It’s important to remember that if you are living in an eco-home, where you have plants, or turf growing on your roof, this will make the problem a lot more complex when it comes to designing the roof. On the other hand, if you’re thinking about spacing for a metal roof, then this solution will be a lot simpler; truss spacing for a metal roof, especially one which is an angle allowing for perfect drainage, is relatively straightforward compared to some of the other things that you might have to design for.
  3. The wind force against the roof might seem like a non-event, but the amount of rain, depending on where you live, will be less than the pressure that the air pressure and wind pressure puts on your roof on a daily basis. Especially if you live in hurricane area, or an area where you routinely get gale force winds, the air pressure and the speed and force of the wind, will impact on your roof considerably. Also, this will therefore impact on whether or not you can have a typical roof truss spacing, or you need something that is more powerful, robust and better reinforced for your particular roof.

Standard roof Truss Spacing

The roof truss spacing standard is important because eighty percent of new homes are built with standard, pre-fabricated trusses. This means that if you’re in charge of repairing or installing roofing trusses, you’ll be expected to hold to these standards.

These standards are as follows: typical roof truss spacing means that they are usually about 24 inches from centre – which means at the centre of one truss, there will be a two-foot gap, or twenty-four-inch gap, until the centre of the next truss.

In addition, each roofing truss will be made of a two by four piece of lumber – or, in areas with expected or usual heavy snow fall, there will be trusses which are two inches by six inches.

Also important to note here is that a two inch in a two-by-four or two-by-six is only one and a half inches in actual weight.

Other buildings:

In a garage, the garage roof truss spacing is usually made in accordance with the local building laws – after all, a garage is an occupied space as much as a house is.

In terms of how this generally operates, it is worth noting that that too is with the same two-by-four material, and the trusses are also going to be around the same spacing’ that is twenty-four inches off centre.

Pole barn roof truss spacing generally tens to operate according to similar spacing principles, though there are some proponents of having higher pole barn roof truss spacing; especially when steel roof truss spacing is concerned, some engineers would argue that it is possible to only have a roof truss spacing of four feet off center – even eight feet has been suggested!

We recommend though if you are involved in pole barn construction and you would like to see if this is possible, you only agree to undertake a project with higher measurements between your roof trusses if you have spoken to a highly qualified architectural engineer and you’re working with a team of builders and engineers who have a vast amount of experience in this area of construction.

The last thing you want is for the roof to be inadequately supported; as your whole structure could collapse, causing no end to the physical, financial, and –god forbid – damage to yours or a loved one’s health – that could be accrued.

It can’t be stated enough that it is necessary for you to go and speak to the local authorities which will be in control of housing regulations before you decide upon how you going to assemble your roof trusses and most importantly, the legislation and regulations which are relevant for any building that has to do be a permanent structure which supports weight.

It might be a headache, it might cost money to have somebody appraise your designs or your ideas, but in the long run it will be more important and it will save you more money. After all, the liability for getting these things wrong can be huge.

Founder & Editor

Hi, I’m Jim. I was a roofing constructor for 20 years, before deciding to start and gather the best content about roofing. I love woodworking and construction and it was only natural for me to start this passion project of mine. Thank you for visitng.