Your building project.
One responsibility.
One contract.

02 / 07·Structure

Load-bearing.
From the same pen.

Structural design arises within the design, not as a later correction. Reinforced concrete, masonry, timber construction — part of the line, not an obligation tacked on afterwards.

HOAI § 51 · DIN EN 1990 ff. · fee zones II – IV

03 / 07·Envelope & building physics

Energy,
that endures.

Thermal protection, sound, material — calculated in the design, not measured after the fact. Eligible for KfW and BAFA funding, planned for the next thirty years.

GEG 2026 · KfW EH 40 / 55 · iSFP-BAFA · DIN 4108 / 4109

04 / 07·Execution

Before the site begins,
it is thought through to the end.

Every junction, every dimension, every item stitched onto a single line of responsibility. Detail before the first day of construction — disputes on site arise from open questions.

Phase 5 execution · phase 6/7 tendering · phase 8 site supervision

05 / 07·Convergence

Concept and construction.
From the same pen.

Architectural service, structure, building physics, energy consulting, CO₂ assessment, Cradle to Cradle, DGNB preparation. Seven disciplines, one fee — several contracts become one.

Fee transparency before commission · § 7 (2) HOAI in text form

06 / 07·Proximity

You speak
with the one who builds.

No sales team between you and the planning. One workshop telephone number, one folder, one contact — from the first sketch to the final invoice.

Reply within 24 h · personally from Robin Henn

07 / 07·Stewardship

Every house,
a decision over
300 tonnes of material.

What we design today lives for two generations. Energy, CO₂, material — as method, not as a label. Eligible for funding today, value-stable tomorrow.

300 t of material per detached house · CO₂ assessment DIN EN 15978 · Cradle to Cradle

Keystone does not sell services.
Keystone sells control over complexity.