Most of a building's heat loss occurs through the building envelope — the external walls, the roof and the floor slabs. Poorly chosen or badly installed thermal insulation materials come back as high heating bills in winter, uncomfortable interiors in summer and, over time, condensation-driven mould, damp and render failure. In most cases the problem is not the material itself but a system that was never matched to the building, the climate and the detailing — combined with workmanship errors during installation.
EREL Yalitim is an insulation contractor and thermal insulation materials supplier based in Esenyurt, Istanbul, Turkey, with an engineering-driven approach built on its founding team's more than 20 years of site experience. Alongside our waterproofing expertise we run a dedicated product sales division: we supply XPS, EPS, rockwool, external wall insulation (ETICS) materials and industrial construction chemicals from the global ranges of our solution partners — materials only for clients who want just the products, or turnkey installation for those who want the complete job.
Our approach is engineering-led, not sales-led. During the site survey we assess the building's current condition, evaluate thermal bridges and condensation risk, and base our thickness and material recommendation on TS 825, the Turkish standard for thermal insulation in buildings — always with the technical reasoning behind it. Whether you are a building management arranging installation, a foreign property owner renovating in Istanbul, or a contractor buying materials in bulk for a site, you decide knowing exactly what you are buying and why.
Where Are Thermal Insulation Materials Used?
Thermal insulation is not just external wall cladding. Every element of the building envelope that loses heat needs to be addressed with its own material and detailing: ETICS systems on the facade, pitched or flat roof solutions on the roof, high compressive strength boards on earth-retaining walls, and products with strong fire performance under cantilevers and on car park ceilings.
Beyond residential projects, thermal insulation directly affects operating costs in industrial facilities. Factory roofs, cold stores, sandwich panel details and service pipework each call for products of different densities and temperature resistance. The EREL Yalitim product sales division supplies insulation materials for all of these needs across Istanbul, and also handles site delivery and bulk, project-based procurement for contractors.
- Facades: ETICS systems (EPS, rockwool boards, adhesive and render mortars, mesh, anchors)
- Roofs: glass wool and rockwool blankets for pitched roofs, XPS system solutions for flat roofs
- Foundations and retaining walls: high compressive strength XPS boards for earth-contact surfaces
- Floor slabs and car park ceilings: non-combustible rockwool boards and spray-application systems
- Industrial facilities: technical insulation products and pipework insulation
XPS, EPS or Rockwool: How to Choose the Right Material
The three most frequently compared product groups on the market are XPS, EPS and rockwool — but the real question is not which is better, it is which is right where. XPS (extruded polystyrene) has a closed-cell structure, so it does not absorb water and offers high compressive strength; that makes it the standard material for details exposed to moisture and load, such as foundations, retaining walls, flat roofs and ground-bearing slabs. EPS (expanded polystyrene) is an economical, lightweight board with higher vapour permeability, and it is the preferred choice for the majority of external wall insulation projects.
Rockwool (stone wool) is mineral-based, classified as non-combustible, and provides acoustic as well as thermal insulation. On the facades of high-rise buildings, between storeys, in zones requiring fire resistance and on building entrance and car park ceilings, rockwool is a standard requirement of technical specifications. Because it is vapour-open, it is also a leading choice in buildings with a high condensation risk.
At EREL Yalitim we select materials from the project, not from the catalogue: building height, facade orientation, interior use, existing damp problems and regulatory requirements are assessed together. Our product sales division supplies XPS, EPS and rockwool from leading global manufacturers in a range of densities and thicknesses, from stock or to order, and our engineering team reports which density belongs in which detail.
- XPS: foundations, retaining walls, flat roofs, ground-bearing slabs; details exposed to water and pressure
- EPS: external wall insulation (ETICS); the economical, lightweight, fast-to-install standard
- Rockwool: facades requiring fire resistance and acoustic insulation, car park ceilings, industrial buildings
- Glass wool: pitched roof voids and pipework insulation
- System accessories: adhesive, base coat render, reinforcing mesh, anchors, corner and joint profiles
External Wall Insulation Materials: Why System Integrity Matters
External wall insulation is not a single board glued to a wall; it is a system made up of adhesive mortar, insulation board, mechanical anchors, a mesh-reinforced base coat, corner profiles and a finishing coat. Pick just one of those layers from outside the system — an incompatible product — and the result shows on site: render cracks, board joints telegraphing through the facade, staining at anchor heads and delamination within a few seasons.
That is why, when supplying ETICS materials, we recommend the factory-tested system packages of trusted global manufacturers: an adhesive matched to the board, mesh of the correct weight, the right anchor type for the facade height, and a finishing coat whose vapour permeability does not conflict with the board. Our product sales division ships every component of the system on a single delivery note, sequenced in installation order, so a missing item never stops the job.
When EREL also carries out the installation, responsibility sits in one place: survey, materials, workmanship and quality control are followed by the same technical team. For contractors and installers who buy materials only, we provide consumption calculations, detail solutions and phone-based technical support during installation — the support that turns product sales from a price war into an engineering service.
Industrial Construction Chemicals and the EREL Difference in Supply
EREL Yalitim's product sales division goes beyond thermal insulation boards. From the industrial construction chemicals ranges of leading global manufacturers we supply waterproofing membranes, liquid-applied waterproofing mortars, injection resins, grouts and repair mortars, joint sealants and floor coating systems. With certified products we cover roof and foundation details, and meet technical insulation needs — all under one roof.
Managing a range this wide means matching the right product to the right detail, and that is where our chemical engineering background comes in. On public and corporate projects where the specification defines a particular system, we present equivalent product proposals backed by technical data sheet comparisons and prepare consumption and quantity calculations for the project. Having installed certified crystalline systems at major infrastructure water reservoirs and thousands of square metres of Proof Membran and Ravaproof systems at industrial facilities is concrete proof that we know the products we sell from the site, not just from the catalogue.
We offer site delivery within Istanbul, project-based pricing and trade account terms for companies that purchase regularly. From thermal insulation to waterproofing and from construction chemicals to technical insulation, this breadth means our clients work with a single point of contact instead of juggling multiple suppliers.
Our Application Process
- 1
Site Survey and Needs Analysis
The building's current condition is inspected on site: facade and roof details, thermal bridges, traces of damp and condensation, and any existing insulation layers. For materials-only supply, we work from the project file and quantity take-off.
- 2
System and Material Selection
Based on TS 825, the Turkish thermal insulation standard, the material type (XPS, EPS, rockwool), density and thickness are determined. Fire regulation requirements, building height and vapour diffusion are factored in, and the system components are proposed as a single-brand package.
- 3
Quotation and Technical Specification
A written quotation covering quantities, consumption rates and installation details is prepared. On corporate projects, compliance with the existing specification is checked; where needed, an equivalent product comparison is presented with technical data sheets.
- 4
Material Supply and Site Delivery
All components of the approved system (boards, adhesive, render, mesh, anchors, profiles) are sourced from our solution partners and delivered to site anywhere in Istanbul, sequenced in installation order.
- 5
Surface Preparation
On installed projects the facade or roof surface is checked: loose render is removed, the surface is trued up, and any water ingress details are waterproofed before thermal insulation begins. The base track profile is installed dead level.
- 6
Board Installation and Surface Layers
Boards are bonded in a staggered pattern and mechanically anchored once the adhesive has cured. Corner and sill details are resolved with profiles; the mesh-reinforced base coat and the finishing coat are applied at the manufacturer's specified consumption rates.
- 7
Inspection and Handover
The installation is checked detail by detail, any outstanding items are completed and the work is handed over in writing. The building management or client is briefed on use and maintenance.
Frequently Asked Questions
How is the price of thermal insulation determined?
The price depends on the surface area, the material type and thickness selected, building height, scaffolding needs and the density of detailing — which is why figures quoted sight unseen are misleading. EREL Yalitim carries out free site surveys across Istanbul and provides a written, quantity-based quotation; call us to book a survey appointment.
Should I choose XPS or EPS?
It depends on the detail. XPS is the right choice for areas exposed to water and pressure, such as foundations, retaining walls and flat roofs; for external wall insulation, EPS is the widespread standard thanks to its economy and vapour permeability. During the survey we report the right choice for your building together with the technical reasoning.
When does rockwool become mandatory?
Fire safety requirements call for non-combustible rockwool on the facades of high-rise buildings, around escape routes and in details such as car park ceilings. It is also preferred on projects with acoustic insulation requirements. We review your project's regulatory requirements together at the survey stage.
Can I buy materials only, without installation?
Yes. EREL Yalitim runs a dedicated product sales division and supplies XPS, EPS, rockwool, ETICS materials and industrial construction chemicals independently of installation. We also give contractors and installers technical support with consumption calculations and detail solutions.
How long does external wall insulation take?
The duration depends on facade area, building height, scaffolding erection and the weather. For a mid-sized apartment building, the process — scaffolding, board installation, render and finishing coat — typically takes a few weeks. After the survey we share a written work programme specific to your project.
Can thermal insulation and waterproofing be done together?
They should be: applying thermal insulation over a surface with water ingress hides the problem rather than solving it. EREL Yalitim specialises in both disciplines. The water problem originating from the foundation, retaining wall, roof or terrace is solved first, then the thermal insulation system is installed. Running both jobs from a single source eliminates detailing conflicts and confusion over responsibility.