It starts the same way every year.

You’re standing in your backyard (or on your balcony), eyeing a pergola, a frame, or some creative DIY contraption and thinking:

“This could totally be a sukkah.”

And then the follow-up thought hits:

“Wait… what about that gap?”

Welcome to one of the most common (and surprisingly manageable) sukkah-building dilemmas: openings between walls, space between structures, and those slightly awkward air pockets that make you wonder if you’ve built a kosher masterpiece  –  or an expensive lawn ornament.

Let’s break it down calmly, clearly, and without reaching for the stress-measuring tape just yet.

When Two Pergolas Become One Sukkah

Modern backyard design has given us many gifts. Fire pits. Outdoor sectionals. String lighting.

And pergolas.

It doesn’t take long before someone has the bright idea:

“What if I put two pergolas facing each other… lay bamboo across the top… and boom  –  instant oversized sukkah?”

On paper, it sounds brilliant. Two parallel frames. A gap between them. Schach (the natural roofing material placed on top of a sukkah) spanning the entire width. Airy. Elegant. Minimal seasonal setup.

But then comes the big question:

Is the space between those walls a halachic problem

The Horizontal Gap: When Open Space Is (Sometimes) Fine

Halachah actually anticipates this kind of situation.

According to Shulchan Aruch (Orach Chaim 630:3–5), a sukkah doesn’t require four fully closed walls. In many cases, three walls are enough – if constructed properly.

Here’s the simplified version:

  • If you have two parallel walls, you can add a third wall perpendicular to one of them.

  • That third wall needs to be at least four tefachim wide (a tefach is a halachic handbreadth – roughly 8–10 cm).

  • It should be placed within three tefachim (about 24–30 cm) of one of the main walls.

That small proximity creates what halachah considers a sufficiently enclosed structure.

And what about the remaining open side?

It can remain open – up to 10 amot wide (an amah is roughly 45–50 cm; 10 amot works out to around 15 feet) before you need an additional fix.

If it’s wider than that, the solution is something called a:

Tzurat HaPetach

Literally, “the form of an entrance.”

This is essentially a halachic doorway – two vertical posts with a horizontal beam across the top. It doesn’t close the space physically, but halachically it defines it as an entrance.

So your double-pergola concept?

Very possibly kosher – with the right third wall placement or a simple tzurat hapetach where needed.

The “Floating” Sukkah: What About Vertical Gaps?

Now let’s tilt things slightly.

Imagine your pergola isn’t perfectly square. Maybe it slopes. Maybe the roofing frame sits higher than the tops of your walls. Maybe there’s visible air between the wall tops and the Schach.

Cue the second wave of anxiety:

“How much air space is too much?”

This question touches on the concept of:

Lavud

A halachic principle that treats small gaps (under three tefachim) as if they’re halachically “closed.”

But here’s where it gets reassuring.

The 10-Tefach Rule: Your Wall’s Golden Number

Halachically, a sukkah wall must be at least 10 tefachim tall (roughly 80–100 cm depending on measurement standards).

As long as:

  • Your walls are at least 10 tefachim high,

  • They begin within three tefachim of the ground (meaning there isn’t a large open gap at the bottom),

  • And your Schach sits above those walls,

Then the vertical space between the top of the wall and the Schach is generally not a problem  –  provided the sukkah’s total height doesn’t exceed 20 amot (about 35 feet) [Shulchan Aruch Orach Chaim 633:1].

In practical terms:

If your walls are solid and high enough, a visible air gap above them does not automatically invalidate your sukkah.

The Schach doesn’t have to rest directly on the wall tops. It simply needs to cover the defined sukkah space.

Two Classic “Gap” Setups (That Actually Work)

Let’s make this concrete.

Scenario 1: The Double-Pergola Build

You have:

  • Two parallel pergolas,

  • A gap of a few feet between them,

  • Bamboo or kosher Schach covering the entire top.

To make it kosher:

  • Add a third perpendicular wall within three tefachim of one side [OC 630:3–5],
    or

  • Install a tzurat hapetach if the open span exceeds 10 amot.

Done properly, you’ve created a defined halachic enclosure without tearing apart your landscaping.

Result: Modern backyard aesthetic meets ancient mitzvah compliance.

Scenario 2: The Slanted Pergola (“Floating Roof” Look)

You have:

  • Walls at least 10 tefachim tall,

  • A pergola frame that slopes upward,

  • Schach resting on the upper beams, leaving visible space above the wall line.

As long as:

  • The walls meet minimum height,

  • They begin within three tefachim of the ground,

  • The Schach covers the sukkah area above,

You’re in good shape.

That small open strip of air? Not a deal-breaker.

Result: Clean architectural lines – still kosher.

Horizontal vs. Vertical Gaps: Different Rules, Different Fixes

One of the biggest misconceptions in sukkah-building is assuming all gaps are treated the same.

They’re not.

Horizontal gaps (between walls) are governed by:

  • Minimum wall dimensions,

  • Placement of the third wall,

  • The 10-amah maximum before requiring a tzurat hapetach.

Vertical gaps (between walls and Schach) hinge on:

  • Wall height (10 tefachim),

  • Lavud near the ground (no large open base),

  • Overall sukkah height limits.

Same word – “gap.”
Completely different halachic mechanics.

A Quick Word on Measuring (Yes, It Matters)

Before you eyeball everything and declare victory, measure.

  • 10 tefachim for wall height is non-negotiable.

  • Three tefachim (lavud distance) determines whether gaps are halachically closed.

  • 10 amot determines when an opening becomes too wide without a tzurat hapetach.

A tape measure is far cheaper than rebuilding the structure on Chol HaMoed.

The Flexible Genius of Halachah

Here’s the bigger takeaway:

Halachah was designed for real life.

People have always built sukkot in courtyards, rooftops, balconies, alleyways, and gardens. The system anticipates imperfect walls, partial enclosures, creative layouts, and structural constraints.

It doesn’t demand fortress walls.

It demands a defined dwelling space beneath kosher Schach.

That’s it.

Practical Tips for the DIY Sukkah Builder

If you’re experimenting with pergolas or custom builds:

  • When in doubt, add a tzurat hapetach. It’s simple and solves a surprising number of enclosure issues.

  • Double-check your wall height before placing Schach.

  • Remember that starting the wall within three tefachim of the ground avoids lower-gap complications.

  • If you’re pushing measurement limits, consult a local rabbi before the holiday – not during the first rainstorm.

A five-minute conversation can prevent seven days of uncertainty.

So…Is That Gap Kosher?

Very often, yes.

A horizontal opening can be managed with a properly placed third wall or a halachic doorway.

A vertical air space above sturdy walls is usually fine if minimum heights are met.

And that sleek, modern pergola setup you’ve been eyeing? It might just become your most elegant sukkah yet.

The key isn’t eliminating every gap.

It’s understanding which gaps matter – and how to work with them.

Because sukkot aren’t meant to be engineering competitions.

They’re meant to be lived in.

Preferably with good food, good company, and just enough shade overhead to remind you that sometimes, structure doesn’t have to be solid to be secure.