Two coefficients decide what your Tulum lot can become. COS (Coeficiente de Ocupación del Suelo) caps how much of the ground a building may cover; CUS (Coeficiente de Utilización del Suelo) caps total built area across all levels. At Selvadentro the limits are COS 35%, CUS 70%, and two levels plus a roof deck — know these numbers before you draw a single line.
I run Selvadentro, so this is a first-party explanation of rules we wrote into our own community regime. But COS and CUS are not our invention — they are standard Mexican planning instruments, and understanding them will serve you on any lot you evaluate, anywhere in Tulum.
What do COS and CUS actually mean?
COS — Coeficiente de Ocupación del Suelo — is the footprint rule. It is the maximum percentage of your lot's surface that construction may occupy at ground level. COS 35% on a 400 m² lot means your ground floor, terraces with roofs, and anything else that touches the ground can cover at most 140 m². The remaining 65% stays unbuilt — garden, jungle, pool, open sky.
CUS — Coeficiente de Utilización del Suelo — is the volume rule. It is a multiplier on lot area that caps the total built area summed across every level. CUS 70% on that same 400 m² lot allows 280 m² of total construction. Combined with a two-level limit, the arithmetic closes neatly: a full 140 m² footprint times two levels reaches exactly the 280 m² ceiling. An uncovered roof deck typically sits outside the CUS count — which is why "two levels plus roof deck" is a meaningful phrase and not decoration.
The two rules answer different questions. COS asks: how much land stays land? CUS asks: how much house exists in total? A lot can have generous CUS and strict COS — that combination pushes architecture upward and leaves the ground to the jungle, which is precisely the intent.
What can you build on a 400 m² or a 1,000 m² lot?
Worked examples at Selvadentro's coefficients — COS 35%, CUS 70%, two levels plus roof deck. Lots here run from 400 m² to 1,673 m², so these bracket the realistic range:
| 400 m² lot | 1,000 m² lot | |
|---|---|---|
| Max footprint (COS 35%) | 140 m² | 350 m² |
| Max total built area (CUS 70%) | 280 m² | 700 m² |
| Levels | 2 + roof deck | 2 + roof deck |
| Ground that stays open | ≥ 260 m² | ≥ 650 m² |
| Example scheme | 140 m² ground + 140 m² upper: a 3-bedroom home | 350 m² ground + 350 m² upper: a large family house, studio and guest wing |
For scale: 280 m² (about 3,000 sq ft) is a generous three-bedroom home with terraces; 700 m² is more house than most families ever use. The constraint you feel in practice is rarely the coefficients — it is the discipline of designing around trees you decide to keep.
Why do these rules exist?
Three reasons, in ascending order of self-interest.
The aquifer. Tulum sits on karst — porous limestone over an underground river system that feeds the cenotes. Every square meter you do not seal with concrete keeps rainwater filtering the way it has for millennia. Selvadentro has nine mapped cenotes inside the project, documented and preserved with specialists; capping ground coverage at 35% per lot is part of what protects the cenote system beneath all of us.
The canopy. Low ground coverage plus a two-level height limit keeps buildings below or within the tree line. That is the difference between a house in the jungle and a subdivision where jungle used to be. Across the whole project, 65% of Selvadentro's jungle stays untouched — the per-lot rules are the same idea at parcel scale.
Your resale value. This is the part buyers underrate. Rules that bind you also bind every neighbor: nobody builds a four-story block wall against your garden, ever. Density protection is value protection — a promise about what the community will still be in twenty years. It is the same logic that makes eco-focused developments outperform: the restriction is the product.
How long do you have to build?
At Selvadentro: there is no deadline to start. Buy in 2026, build in 2032 — that is your call, and land does not depreciate while you wait (for reference, our pricing moved from $119 USD per m² at launch in May 2025 to $167 USD per m² today). Once you do start construction, the rule is a maximum of two years to finish. The reason is neighborly, not bureaucratic: a community where every build has an end date is never a permanent construction site. Half-finished concrete shells, familiar from other corners of Tulum, are what this clause exists to prevent. More practical questions like this are answered in our FAQ.
What do design guidelines protect beyond the coefficients?
Numbers alone do not make a place. Community design guidelines typically govern the quieter variables: noise during and after construction, setbacks and privacy between homes, lighting that does not bleach the night sky, materials and colors that sit calmly in the landscape, and how much native vegetation a build must preserve or restore. At Selvadentro these guidelines bind every owner through the community regime — the point is jungle integration, and the effect is that your neighbor's choices cannot degrade your silence. That, as much as the gate, is what a private community means.
What about municipal permits and environmental rules in Tulum?
Community rules sit on top of public ones, never instead of them. Any build in Tulum requires municipal construction licensing, and projects in this region carry environmental considerations — vegetation, drainage, the aquifer — that authorities review. Regulation here has teeth: in September 2025, Quintana Roo's urban-development ministry SEDETUS publicly listed 26 Tulum developments over permit concerns, and its updated bulletin of September 16, 2025 confirmed 14 of them — Selvadentro among them — fully compliant after review. Verify the master development's papers before you ever think about your own building permit; a house drawn to perfect coefficients on unpermitted land is still the wrong house.
The short version
COS is footprint, CUS is total area, and at Selvadentro the pair reads 35/70 with two levels plus a roof deck — enough for a 280 m² home on the smallest lot, with no pressure on when to start and two years to finish once you do. If you want to test the math against a real parcel, current lots in Suspiro list sizes from 400 m² to 1,673 m². Bring your architect's questions — these rules are the ones we most enjoy explaining.