DIY Builds
Photo by Ryutaro Tsukata Pexels Logo Photo: Ryutaro Tsukata

How high should vent pipe stick out of roof?

The plumbing code requires plumbing vents to terminate at least 12″ above the surface of the roof to help prevent the vents from getting blocked with snow, but the higher the vent the greater the potential for getting blocked with frost.

How much does FL Studio cost?
How much does FL Studio cost?

There are four editions of FL Studio available: Fruity, Producer, Signature & All Plugins Edition. Prices start at $99 USD and range up to $499...

Read More »
Why you should learn woodworking?
Why you should learn woodworking?

You'll Know How to Repair Things Older wooden objects can become rough around the edges as the years go by, and instead of repairing them, you can...

Read More »

When there’s a long period of sub-zero temperatures in Minnesota, plumbing vents often stop working. The problem is that plumbing vents can get completely blocked shut with frost when it’s very cold outside for a long period of time. I previously wrote about why houses need plumbing vents, which should help to explain why this stuff matters. This first photo shows how the frost begins to form. This is a 3″ steel vent pipe at an old house in Minneapolis. Frost was just beginning to form at the top, and could actually be seen from the ground. This next photo shows a 4″ cast iron vent pipe at a multi-family home in Saint Paul. It wasn’t completely blocked with frost… yet. As the frost keeps accumulating with very cold temperatures, eventually the vents get completely blocked with frost, which prevents them from ‘venting’. I’ve included several photos here to show that all types of vents can be subject to frost closure, given the right weather conditions. The tried-and-true method of preventing plumbing vents from getting blocked with frost is to increase the size of the vent before it protrudes through the roof. Here in Minnesota, the smallest size vent that can penetrate the roof surface is 2″, according to Minnesota Plumbing Code section 4715.2530, Subp.2. Keep in mind, however, that this is the minimum requirement. That’s all the code is; a minimum requirement. As you can see from the photos above, this isn’t necessarily a formula for success. Many old-school plumbers in Minneapolis and Saint Paul knew about this problem, and it was common for old houses to have vents that were significantly increased in size before penetrating the roof, just to help prevent the vents from getting blocked by frost.

The photos below show how this looks in real life.

I’ve also seen a product sold to help prevent frost closure, called a Sewer Skewer. It’s basically a stick of copper tubing with a “T” fitting at the top. Copper absorbs heat from the sun and keeps things warm enough to prevent frost, apparently. I’ve never seen one in action before, but it seems like a good idea. Another way to help prevent plumbing vents from getting covered over with frost is to keep them short. The plumbing code requires plumbing vents to terminate at least 12″ above the surface of the roof to help prevent the vents from getting blocked with snow, but the higher the vent the greater the potential for getting blocked with frost. In other words, the best height for a plumbing vent is 12″ above the surface of the roof, and the wider the pipe the better. If you look up at your roof from the ground and you can see frost accumulation at the plumbing vents, don’t get too worried about it. The frost will go away as soon as it warms up a little; maybe later in the day, definitely by April.

Are floor joists load bearing?
Are floor joists load bearing?

Floor joists are designed to be load-bearing. They act as the support for upper levels, often transferring weight to vertical supports within a...

Read More »
Does a shed increase value?
Does a shed increase value?

A shed can even help to increase your asking price when you decide it's time to sell. In fact, some professionals estimate that a new shed could...

Read More »
Can I build my own shed?
Can I build my own shed?

Yes, with the right plans you can build your dream shed.

Learn More »

How do you attach a shed to a concrete slab?
How do you attach a shed to a concrete slab?

Newly-Built Shed Step 1: Get Your Galvanized Anchor Bolts. If you are building a normal shed using 2x4s, then 1/2-inch anchor bolts will do just...

Read More »
What kind of wood to use for floor joists?
What kind of wood to use for floor joists?

Lumber Grade Lumber graded as #2 is the most common choice for floor joists and other framing lumber. It has more knots and defects than higher...

Read More »
Should I paint the floor of my shed?
Should I paint the floor of my shed?

Painting the shed floor helps protect and seal the wood, it reduces splinters, makes it easier to clean, and it looks so much better. Caulk any...

Read More »
Does a USB heater exist?
Does a USB heater exist?

You can also find USB (rechargable) heaters for camping, USB personal heaters, as well as USB space heaters. USB powered heaters are electric,...

Read More »