Every home has a roof and we all expect them to remain in place, firmly and securely above our heads. But if you live in a place like South Eastern Ontario that sees significant snowfall, you may be asking yourself how much weight can a roof hold? Can my roof support my weight if I stand on it?
Whether you are worried about snow accumulation or need to get on the roof for some reason, it is important to understand how much weight the roof will hold.
That vast majority of roofs will be built to hold a minimal amount of weight as laid out in the provincial building codes. However, exactly what this means for you, your roof, and your safety should you climb abroad, will depend on a few different things.
To help you determine if your roof can support your weight, and exactly how much weight it can support overall, we’ve put together this detailed guide.
How Much Weight Can My Home’s Roof Support?
To understand exactly how much weight your home’s roof can handle, you should consult local building codes. Your home would have been built to these codes, giving you a clearer picture.
Calculating the exact load-bearing capacity of your roof is a rather complicated mathematical task as it depends on a number of factors like the materials used and the slope of the roof.
When considering how much weight your home’s roof can support, it is important to factor in both dead load and live load. A dead load is the weight of the structure and materials as well as the weight of any permanent fixtures or attachments like HVAC units. A live load is any temporary weight on the roof like snow, people walking around, and any equipment the people bring up there with them.
A roof must be built to withstand both types of load.
For most residential buildings, the roof should be able to support a live load of at least 1.9 kPa or around 20 pounds per square foot for a wood or shingled roof. A roof made of more sturdy materials, like clay or metal, will be able to hold closer to 27 pounds per square foot.
To help you get a better sense of your specific roof, here’s a closer look at the weight-bearing of some common roof types.
Gable Roof
A gable roof consists of two sides, sloping down towards the walls. These types of roofs often have a significant slope to them. These slopes are excellent for preventing snow accumulation as it typically slides right off, but they can be complicated when attempting to determine weight-bearing capacity.
Load limits are calculated with the assumption that weight is pushing downward, uniformly, on a roof’s horizontal surface. With a gable roof, there is not as much horizontal surface area so the load must be adjusted to account for this.
Typically, with slopes greater than 4:12, the live load limit will be adjusted downward to allow for a greater dead load.
Concrete Roof
Concrete is a fairly strong substance but it is not without weight limitations. In commercial buildings, concrete roofs can generally handle 1,200 pounds per square foot. But, this can be very different in residential properties.
The amount of weight a concrete roof can hold depends on the thickness of the concrete, the age and condition of the roof, and the types of reinforcement used.
Flat Roof
Like concrete roofs, the load-bearing capacity of your flat roof will depend on a range of factors like the size of the roof, the building materials, and the roofing system.
Like all roofs, flat roofs will be built to withstand at least 20 pounds per square foot but it is possible to exceed these limits with the accumulation of snow, rain, or debris.
Homeowners with flat roofs should pay close attention to things like snow accumulation and consider snow removal.
Typically, flat roofs will also have a concentrated load capacity. This is the amount of weight that can be held at a single point on the structure. Concentrated loads in Ontario are 1.3 kN or around 300 pounds.
Hip Roof
With hip roofs, the roof slopes down from a central ridge toward the exterior walls.
Generally, the slope will not be as steep as with gabled roofs but there is still very little horizontal space, meaning slope must be factored into any weight calculations.
Snow loads must also be added to the equation. While the pitch and slope of the roof do allow for snow and rain to slide off, it is still possible for heavy accumulations to occur.
Mansard Roof
A mansard roof is a type of hip roof. It is double pitched, where the lower section is steeper than the upper.
While architecturally impressive, these roofs can be complicated from a load-bearing perspective. While the lower section has a steep slope, the upper part of the roof is relatively flat and can be compromised by the accumulation of snow and debris.
A-Frame Roof
A-Frames consist of two downward-sloping sides that extend from the centre ridge to the ground. Essentially, A-Frame roofs also act as exterior walls.
The slope more or less guarantees that snow, rain, and debris will not be an issue.
As with all other roof types mentioned here, the exact load capacity of your A-Frame roof will depend on the pitch and slope, the materials used, and the number of trusses or reinforcements inside the structure.
Can My Roof Support My Weight – Signs That Your Roof is Failing
Before you get up on your roof to put out holiday decorations, retrieve errant toys from the neighbourhood kids, or start thinking about adding solar panels or changing roofing materials, you should look for signs of damage or age that might prevent your roof from properly handling this increased weight.
Here are a few things to look out for:
Roof Sag
Roofs tend to fail little by little. And sagging is a clear indication that things are starting to go awry.
If you notice dips or bowing, there is definitely an issue. If you are on the roof, and it feels soft or springy under your foot, get off the roof immediately for your own safety.
Your best bet is to hire a roofing contractor to come and assess the situation.
Cracks in the Ceiling or Brick
Cracks in your ceiling or in brickwork can be a sign of stress. It means something is putting pressure on these structures. It could be a load-bearing issue or something wrong with your building’s foundation, which, in turn, will impact the integrity of the structure, including your roof.
Roof Leaks
A leaky roof is a sign of damage. Leaks indicate that water is making its way into the roofing structure. This will not only impact the weight-bearing capacity of your roof but also impacts the structural integrity.
Roof leaks often go hand in hand with sagging. If you notice leaks, call a roofing professional immediately.
Unusual Sounds From Roof Area
Creaking, groaning, moaning, and squeaking can all be indicators of stress on the roof. If you hear any sounds that are out of the ordinary, especially if you are walking on the roof, it is time to call a professional in to take a look.
Ways to Reinforce Your Roof to be Stronger
For very old or damaged roofs, the best thing you can do to restore their strength is to get a roof replacement.
However, if that is not currently in your plans (or budget), there are a few things you can do to bolster the strength of your current roof, allowing it to handle a little bit more weight than it would have otherwise.
Strengthen Existing Trusses
Attach 2x4s to the existing trusses. Do this from one end of your home to the other. This will create more stability to the structure and can help the roof support additional weight.
Repair Damaged Shingles
Repairing and replacing damaged shingles will help keep your roof strong by preventing moisture from seeping in underneath and causing rot.
Rot and mould can significantly weaken your roof over time.
Apply Construction Adhesive
A short-term solution for repairing damaged shingles or roofing tiles is the use of construction adhesive.
Should you find loose shingles or that you need to perform a quick repair, gluing them in place can maintain roof strength until you are able to get someone out to take a closer look.
Call Energy Kingston Exteriors
Roofs are built to withstand a specific amount of weight. What exactly your roof can handle comes down to a few different factors like the type of roof you have, the roofing materials used, the health of the roof, and the way it is reinforced.
There are many reasons people want to know how much weight a roof can hold. Perhaps you are looking to make some renovations or maybe you have seen signs that your roof is weakening. But the truth is, it can be very dangerous to get up there and poke around yourself. Depending on the situation, the roof may not support your weight.
Professional roofers, like Energy Kingston Exteriors, know how to examine your roof safely and securely. They can determine how much weight your roof can handle, how to strengthen weaknesses, or they can replace your roof if that’s the only viable solution.
Do not leave your home or your safety to chance, contact Energy Kingston Exteriors to find out exactly what your roof can take!