Grumbach

What Grumbach does

Karl Grumbach GmbH & Co. KG is a family-owned German industrial company headquartered in Wetzlar-Münchholzhausen that develops, manufactures, and distributes sanitary and flat roof products. The company operates two product divisions. The Flat Roof Program (Flachdachprogramm) is marketed as the largest roof drain program in Europe and spans standard drains, balcony drains, retrofit drains, parapet (Attika) drains, green roof drainage, ventilation products, and special solutions. The Sanitary Program (Sanitärprogramm) comprises PUR pre-wall installation elements (corner blocks, standard blocks, and SLIM-Blocks), floor-level shower systems, prefabricated showers, and complete prefabricated bathrooms. Revenue is generated through hardware sales to sanitary and roofing wholesalers (Sanitärgroßhandel, Bedachungshandel), direct contractor accounts (Dachdeckereien, Sanitärinstallation), and end customers in hotels, care facilities, and residential renovation; pricing is not publicly disclosed and is communicated via downloadable catalogs and direct sales contact.

The company's products are built on a proprietary PUR (polyurethane hard integral foam) technology platform that delivers thermal insulation, noise reduction, and condensation protection without CFCs, supplemented by stainless steel for certain drain systems. Notable technical differentiators include the SLIM-Block at 20 cm width (marketed as the narrowest wall-mounted WC pre-wall element on the market), the Kombi-Gully combining ventilation and drainage through a single roof penetration, eccentric and power-drain variants for multi-storey drainage, and prefab bathroom units. The intellectual property base includes 30+ registered utility models (Gebrauchsmuster) and 13 patents originated under founder Emil Grumbach, accumulated over more than 45 years of industrial production. The firm is currently managed by the third generation (Susanne and Lazaros Konstantinidis), with the fourth generation (Simon Gerd Konstantinidis) joining as shareholder in 2023.

Name

Grumbach

Legal name

Karl Grumbach GmbH & Co. KG

Website

https://grumbach.net

Company type

Private

Founded year

1938

Operating status

Operating

Headcount range

11–50 employees

Short description

Karl Grumbach GmbH & Co. KG is a family-owned German industrial manufacturer of PUR-based sanitary pre-wall elements, prefabricated bathrooms and showers, and flat roof drainage products, serving plumbing and roofing wholesalers, contractors, and end users across Europe.

Ownership category

akta.pro rank

Product category

Sanitary and flat roof building products

NAICS

Roofing, Siding, and Insulation Material Merchant Wholesalers (42333)

SIC

Wholesale-Lumber & Other Construction Materials (5030)

akta.pro primary industry

Polyurethane (PU) Rigid Foam Manufacturing (IMANAIAD)

Keywords

• Flat roof drainage
• Sanitary pre-wall elements
• Prefabricated bathrooms
• Shower floor systems
• Polyurethane building products

Headquarters

HQ city

Wetzlar

HQ country

Germany

HQ region

Europe

Offices1 record

Markets served

GTM type

B2B

Offering type

Hardware or Manufacturing

Cost components

Supply Chain, Personnel, Operations, Technology or R&D, Marketing or Sales, Infrastructure

Revenue model

1. Flat Roof Products: Manufacture and sale of roof drains (Dachgullys), roof ventilators, and accessories for drainage and ventilation of flat roofs. Products include standard drains, balcony drains, attic drains, green roof drains, and special solutions. The company claims to offer the largest roof drain program in Europe.
2. Sanitary Products: Manufacture and sale of sanitary products including sanitary blocks for pre-wall installation (WC stones, corner blocks, SLIM-Blocks), shower floor systems for barrier-free showers, prefabricated bathrooms (Fertigbäder), and prefabricated showers (Fertigduschen).

Go-to-market motion2 records

Distribution channels6 records

Marketing channels7 records

Core offering

Karl Grumbach GmbH & Co. KG manufactures and distributes PUR (polyurethane hard integral foam) and stainless-steel products in two divisions: the Flachdachprogramm (roof drains, balcony drains, parapet/attic drains, green-roof drainage, ventilation elements, special solutions, and accessories — claimed as the largest roof drain program in Europe) and the Sanitärprogramm (PUR sanitary pre-wall blocks, shower floor systems, prefabricated showers, and prefabricated bathrooms). The company sells to sanitary and roofing wholesale trade, plumbing and roofing installers, and project customers such as hotels, nursing homes, and industrial buildings across Germany and Europe.

Product overview

Grumbach is a family-owned industrial company (Karl Grumbach GmbH & Co. KG, founded 1938) that develops, manufactures, and distributes innovative sanitary and flat roof products. The product portfolio consists of two main divisions: (1) Flat Roof Products (Flachdachprogramm) - the largest roof drain program in Europe, offering Standard-Gullys, Balkon-Gullys, Sanierungs-Gullys, Attika-Gully-Programm, Gründach-Entwässerung, Be- und Entlüftung, and Sonderlösungen (special solutions like Kombi-Gully, Exzenter-Gully, Alpha-Gully, Edelstahl-Gully); and (2) Sanitary Products (Sanitärprogramm) - encompassing Sanitärbausteine (PUR pre-wall elements including Eck-Steine, Steine, and SLIM-Blocks), Duschbodensysteme (shower floor systems with elements, support frames, and bath drains), Fertigbäder (prefabricated bathrooms in Universal, Basis, Sparta, Frankfurt, Individual, and WC-Kabine variants), and Fertigduschen (prefabricated showers in Standard, Senior, and Souverän models). The company also offers EntwässerungPlus, an online drainage calculation tool following DIN 1986-100. All PUR products are thermally insulated and CFC-free. The flat roof drains and sanitary blocks are the company's core competencies with over 45 years of development and production experience.

Differentiator

Problem solved

Functional benefit

Products and services

• Flachdachprogramm (Flat Roof Program) Comprehensive flat roof drainage product program covering roof drains (Gullys), roof ventilators, and accessories for draining and venting flat roofs, balconies, terraces, green roofs, and parking decks — claimed as the largest roof drain program in Europe.
• Sanitärbausteine (Sanitary Pre-Wall Blocks) PUR (polyurethane) pre-wall installation elements for sanitary facilities, including triangular Grumbach Eck-Steine corner blocks, rectangular Grumbach Steine, and SLIM-Blocks (20 cm width), for WC, washbasin, bidet, urinal, and battery installations.
• Duschbodensysteme (Shower Floor Systems) Floor-level shower system consisting of PUR shower floor elements with integrated drain and odour trap, EPS 35 height compensation plates, and steel-tube support frames, designed for quick installation of barrier-free showers.
• Fertigduschen (Prefabricated Showers)

Quantifiable outcome

• Attika-Jumbo-Gully achieves drainage capacity up to 12 l/s at 55mm accumulation height
• +3 more outcomes

Segments6 records

Ideal customer profiles3 records

Technology focussed No

API detail

Has API

No

API docs

API detail

Core technology

AI maturity

App detail

Feature9 records

Scale indicators4 records

Recent moves6 records

Expansion highlights6 records

Broad incumbents

• ACO: European specialist in drainage systems for buildings, infrastructure, and landscaping. Overlaps with Grumbach's flat roof and balcony drainage ranges at the larger-incumbent tier, especially in commercial and parking-deck applications.
• Geberit: Swiss-listed global leader in sanitary technology (pre-wall installations, cisterns, piping). Direct overlap with Grumbach's PUR sanitary blocks — Grumbach's Eck-Steine and Standard blocks are explicitly compatible with Geberit Sigma and Omega activation plates, indicating shared end-customer and substitute-product risk.
• Viega: Germany-headquartered global pipe and drainage systems manufacturer with significant presence in roof drainage and DWV fittings. Competes with Grumbach's Flachdachprogramm on Attika/parapet drains and siphonic drainage.
• Wavin: European plastic pipe and fittings major (now part of Orbia). Competes with Grumbach's PUR-based DWV roof drains at the larger-incumbent tier via broader product portfolios and stronger international distribution.

Direct peers

• HL Hutterer & Lechner: Austrian manufacturer of roof drains, floor drains, and siphonic drainage systems. Comparable regional specialist to Grumbach's flat-roof portfolio with overlapping DACH trade-channel presence.
• TECE: German manufacturer of pre-wall installation systems, shower drain channels, and plumbing technology. Closest mid-sized specialist comparable to Grumbach's sanitary block + shower floor portfolio, with similar trade-channel distribution in DACH.
• Jackon Insulation (JACKOBOARD): Manufacturer of XPS-based pre-wall construction boards and shower elements (JACKOBOARD). Emerging alternative-material competitor to Grumbach's PUR sanitary blocks and shower floor systems, particularly in bathroom-renovation channels.
• Dallmer: German family-owned manufacturer specializing in roof and floor drainage systems (attic drains, balcony drains, shower channels). Highly comparable niche specialist competing head-to-head with Grumbach's Flachdachprogramm.
• wedi: German manufacturer of XPS-based pre-wall elements and floor-level shower systems, including the wedi Fundo shower range. Closest direct competitor to Grumbach's Duschbodensysteme and Sanitärbausteine, with overlapping bathroom-renovation distribution.
• Sita Bauelemente: German specialist for flat roof drainage and ventilation (Gullys, Aufstockelemente, Notentwässerung). Direct segment overlap with Grumbach's Standard-/Attika-/Sonder-Gullys and roof ventilator lines.

Market position

Strengths5 records

Weaknesses5 records

Competitive moat5 records

Key risks5 records

Key highlights6 records

Customer concentration

• YouTubeyoutube.com/channel/UCTmzbe6SOsnJT11W5VPX0gw

Revenue estimate

Valuation estimate

Number of profiles

Profiles4 records

Funding overview

Funding rounds

Investors

Funding detail is available on the Subscription and Enterprise plan.Contact sales →

M&A

Investments

M&A and investment is available on the Subscription and Enterprise plan.Contact sales →

Frequently asked questions about Grumbach