Somebody in Evergreen asks us this every spring, usually after a storm that took down a neighbor’s covered patio. They want to know why we are talking about beam sizing and footing depth when all they asked for was a nice space under the deck.

Fair question. Here is the plain answer: the structure has to hold up whatever the sky puts on it, and up in the foothills the sky puts down a lot more than most people expect. Understanding that is the difference between a space you use for twenty years and one you are cleaning up in April.

Elevation changes the number on the plan

A structure that would be fine in a Denver back yard is not automatically fine a few thousand feet higher. The design load a builder works to climbs as you gain elevation, and the foothills sit far enough above the metro that the same span, the same post spacing, and the same footing depth stop being adequate. That is why a plan drawn for a flatland lot does not transfer up the canyon unchanged.

Ground snow load versus roof snow load

These two terms get used interchangeably and they should not be. Here is the difference in plain language.

Ground snow load is how much weight a square foot of open ground is expected to hold in a bad year. It is a regional number pulled from decades of records, and it is the starting point for everything else.

The ground number tells you what the neighborhood gets. The roof number tells you what your beams have to hold.

The storm that actually does the damage

Ask most people about mountain snow and they picture January. Deep, dry, powdery. That snow is genuinely not the problem. It is light, and a good amount of it blows right off an exposed structure before it ever settles.

March and April are the problem. Late-season foothills snow comes in wet and dense. It lands with real weight, it packs down instead of shedding, and it hangs on for days while it melts a little in the afternoon and refreezes overnight. Every one of those cycles adds water weight to a covering that is already loaded.

The three answers that actually matter

Load handling is not complicated. It is a chain: the covering hands weight to the rafters, the rafters hand it to the beams, the beams hand it to the posts, and the posts hand it to the ground. The chain is only as good as its weakest handoff, and there are three places it usually goes wrong.

• Post spacing. Every foot you add between posts asks the beam above to work considerably harder. Tightening the spacing is often cheaper and stronger than upsizing lumber, and it is the first thing we look at on a heavy-load site.
• Footing depth below frost. Foothills frost runs deeper than metro frost. A footing that stops short heaves through the freeze cycle, posts start moving at different rates, and the frame slowly racks itself out of square. Surface-lagged posts on a slab do not belong on a mountain property.
• Beam sizing for the real number. Beams get sized off the roof load, not a catalog default. That means somebody actually ran the calculation for your elevation, your exposure, and your span.

Drifting against the house wall

Here is the one that surprises people. Snow does not sit evenly. Where a covered structure meets your house, the wall interrupts the wind and snow piles up in that corner, sometimes at two or three times the depth of the open field a few feet away.

That drift zone is a concentrated load in exactly the place where an attached structure has its most important connection. The ledger and the first bay of framing need to be sized for the pile, not the average. If a plan shows one uniform load across the whole structure, ask about the wall.

Where the snow goes when it finally lets go

Eventually the sun comes out and everything on top slides off at once. Nobody thinks about this until they have watched it happen, and then they think about it constantly.

This is a good part of why our underdeck pergola work in Evergreen gets planned around the site rather than pulled off a shelf. Where the water and snow leave the structure drives the whole layout.

What to ask any contractor to show you

You do not need to become an engineer to protect yourself here. You need four answers, and a contractor who builds up here will have them ready.

• What ground snow load did you use, and where did that number come from for my address?
• How deep are the footings going, and how does that compare to frost depth in Evergreen?
• What is the post spacing and the beam size, and what span are those sized for?
• Where does the snow land when it sheds, and what is underneath that spot?

Vague answers to those questions are the answer. If somebody cannot tell you where their load number came from, they used a default, and a default was written for somewhere flatter than here.

Why a big-box kit is the wrong tool up here

Kits are engineered for the national average, and the national average lives thousands of feet below Evergreen. The instructions assume a shallow frost line, a modest snow load, and a flat installation. None of those assumptions hold on a foothills lot.

The weakness usually is not the post, which is the part people inspect. It is the beam span and the connection hardware, which are the parts nobody looks at in the box. Upgrading the posts on a kit leaves the actual weak link untouched, and you find out which link that was on a wet April morning.

We are employee-owned, which means the people who set your posts are the people whose name is on the work, and we back our workmanship with a lifetime warranty. That warranty only makes sense if we build things that hold. It is why we would rather have this conversation before the design than after the storm. Come see finished work in our project gallery, or look at what we build across Evergreen and the surrounding foothills.

If you want the real numbers for your property, set up a free consultation and we will walk the site with you. No pressure attached, and you will come away knowing exactly what your lot can carry.

Common questions