You’ve got roof pitch questions, we’ve got answers.
Whether you’re just interested in knowing more about the importance of your roofing materials or you’re trying to gather more info on how to raise a roof pitch or roof slope, this is the article for you.
What is roof pitch?
There are many different types of roofs out there, such as flat roofs, the pitched roof, the built-up roof, the gable roof, and so on and all have a different roof pitch. Plainly put, the roof pitch is how steep a roof is. Standard roof pitch varies among geographic locations, climatic conditions, etc., so there’s no one-size-fits-all roof.
How to read roof pitches
You’ll probably see something like a 4/12 roof pitch. This means that the roof rises 4 inches for every 12 inches it runs.
The roof pitch is not to be confused with the pitch angle. Unless you’re incredibly talented at math, you’ll have to do a bit of calculating to get the pitch angle.
What is roof pitch angle?
So, the 4/12 roof pitch angle is about 18.4°. A 3/12 roof pitch angle is about 14°, so on and so forth.
4/12 is quite typical. Anything under 3/12 is a low pitch roof. Anything above 6/12 is a steep roof pitch since it becomes harder to walk on the roof.
How to find the pitch of your roof
It’s pretty easy, to be honest. Get a level and some measurement tape. Mark 12 inches on the level. Place one end of the level against the roof, then raise it until the bubble in the level is, well, level. Then, with your tape measure, tape directly from the 12-inch mark down onto your roof. That will tell you the #/12 roof pitch.
Benefits of low vs. steep roofs
Advantages of a low pitch roof:
- Easier to walk on.This one is a given. If you want to use your roof for other purposes, such as a garden or bar area, it would be best to have the pitch angle as low as possible. You can’t enjoy the city view sitting on a steep angle!
- Improved heating and cooling. Normal or steeply pitched roofs create extra space in the structure. This space, of course, fills with air. Air is susceptible to relatively quick heating and cooling when exposed to external temperatures and will affect the temperature below the roof (re: where you and other people are most likely to be.) A low or no pitched roof eliminates that dead space, removing that space’s impact on the temperature below it.
- Lower installation costs. Low slope or flat roofs need less material to build, as you won’t need large trusses. This reduces labor costs (for you or hired workers) in handling and installing these trusses. Also, rolling out, covering, sealing roof material is faster than installing individual shingles.
The disadvantage of a low roof:
- Exacerbated weathering. Water and ice will sit on a flat roof more so than a pitched roof. This means that water has more opportunity to seep into cracks and crevices or attract pests. However, because the roof is flat, it will be easier to climb up and fix roof issues, so at least there’s that.
Advantages of steep roof:
- More space.The area under the steep roof can be converted into an attic, used for storage or even living purposes. It’s a good way to increase the value of your home or to simply get the most out of your property’s space.
- Let snow load. If you live in an area with heavy snow, a steep roof discourages snow from accumulating. Low or average roof pitches allow the snow to get heavier on the home, causing structural damage after successive snow seasons. On a steep roof, however, snow will slide right off.
- Dryer roof. As with snow, water will slide right off too. This will keep the roof drier overall and discourage spontaneous roof leakages.
Disadvantages of a steep roof:
- As mentioned previously, a steep roof is harder to walk on, making repairs more difficult.
Changing roof pitch
Low roof pitches have their advantages—most people have average or steeply pitched roofs for a reason. If you already know you have low pitch roof, you might want to increase the roof pitch. But how should you go about doing it?
Just note, changing roof pitch requires good carpentry skills and ample roofing knowledge. While we can’t supply the former, we can give you the latter (pun intended).
How to pitch a flat roof
The pitch of a flat roof is between 1-3/12. Whether you’re doing it for homerenovating purposes or repair concerns, here’s a quick guide on how to raise the roof (not the dancing kind).
To increase that, get some rigid foam insulation. Strip your existing roof down to the wood covering. Install the rigid foam panels, ensuring various tapers and thicknesses.
Create a single slope from one end to another using the rigid foam panels. Then align more panels, extending the original slope across the roof. Use mechanical fasteners or adhesive to fasten the tapered panels to the roof.
Depending on local building codes, apply vapor or thermal barriers. You can use ethylene propylene diene monomer rubber, polyvinyl chloride, thermoplastic olefin, etc. to cover the tapered roof. If you have anything like chimneys or vent pipes, install metal flashings around the protrusions to prevent leakages.
That’s a quicker way to increase roof pitch. Other methods include removing roof coverings, rafters, and trusses and installing completely new ones. That may work better depending on your situation. If you want to discuss other low roof pitch options, you can contact a local professional roofer.
How much pitch should a gutter have?
Once you’ve re-pitched your roof, the next thing to concern yourself with is the gutters. Efficient gutters have a pitch that allows rainwater to drain away from the roof and home. This is essential for preventing floods and leaks, avoiding the harm of nearby landscapes, and protecting your home’s foundation. Don’t take gutters lightly.
Most roofers will set the slope at 1 quarter inch per 10 feet of guttering. So, if you have 30 feet of guttering, your downspout should be 0.75 inches lower than the other end (0.25 x 3 = 0.75). Simple enough, right?
Roof pitches matter
Not many homeowners think about their roof pitch often (heck, not many people even know it exists), but understanding and maximizing your roof’s pitch increases your home’s longevity and lowers the amount of time you’ll have to see a roofer. Reread this article and take the time to learn more about roof pitches.