Istanbul Bathroom Renovation Guide: What Experts Must Know

1. Pre‑Project Survey & Planning

During the free site survey we examine the building’s structural type (reinforced concrete, masonry, timber, stone) and floor‑to‑ceiling height. In older properties we check wall thickness, existing plumbing routes and potential asbestos hazards.

Based on these data, an architect‑engineer approval, waterproofing system and layout alternatives (2‑3) are drafted. A written fixed‑price quote, scope and payment schedule are finalized at this stage.

• •Check building type and floor‑to‑ceiling height
• •Identify existing plumbing and possible asbestos
• •Architectural approval and waterproofing system selection

2. Permits & Regulations

Under Istanbul Metropolitan Municipality’s “Zoning and Construction Supervision Regulation,” a bathroom remodel does not require a “Business Opening Permit,” but any alteration to water lines must be covered by a “Water & Sewerage Works Permit.”

Without municipal approval, wall demolition, waterproofing and plumbing changes will not pass building inspection and can result in penalties.

• •Apply for water & sewerage permit
• •Construction inspection report (if required)
• •Energy‑efficiency label (A+ fixtures)

3. Demolition & Infrastructure Works

Old tiles and plasterboard are removed carefully to avoid damaging any steel framing. For attic bathrooms, roof waterproofing is inspected and additional insulation added if needed.

For new plumbing, PPR (Polypropylene Random) pipes are used; 25 mm diameter, 1 m cuts typically account for about 40‑45 % of the budget, balancing the remaining cost for cabinets, tiles and lighting.

• •Wall and floor demolition
• •Re‑routing water and drain lines
• •Thermal and acoustic insulation (especially in old stone buildings)

4. Waterproofing & Floor Preparation

Considering Istanbul’s humid climate, a two‑layer membrane (primer + liquid membrane) is mandatory. After curing, a cement‑based screed (minimum 5 mm) is applied.

A 30 mm XPS insulation board is installed beneath the floor; this raises energy savings and comfort by roughly 10‑12 %.

• •Primer + liquid membrane application
• •Cement screed layer
• •Thermal insulation board (XPS)

5. Fixture Installation & Finishing

Tiles are laid using a “liquid mortar” method that does not compromise waterproofing. In compact bathrooms, about 30‑35 % of wall area is tiled; the rest is finished with waterproof acrylic paint.

Fixtures are chosen with A+ LED lighting and water‑saving faucets/toilets. After installation, a leak test at 3 bar pressure and a ventilation performance check (minimum 15 m³/h) are performed.

• •Tile laying (liquid mortar)
• •Waterproof acrylic paint
• •LED lighting and water‑saving fixtures

Frequently Asked Questions

How is asbestos risk checked in old buildings during bathroom renovation?

A municipality‑approved lab samples wall and ceiling sections. If results are negative, work proceeds; if positive, a certified asbestos removal contractor handles the removal and the entire process is inspected by the municipality.

Which waterproofing membrane is recommended for bathroom renovations?

For Istanbul’s climate, a polyurethane‑based liquid membrane combined with a polyester‑fibred primer offers the most durable solution; it requires at least 24 hours curing.

When is a building inspection required during bathroom renovation?

After demolition, two separate inspections are mandatory: first for waterproofing, second for plumbing and finishing works.

Which cost items take the largest share of the budget?

Typically, plumbing accounts for 40‑45 %, tiles and flooring 20‑25 %, cabinets and furniture 15‑20 %, and labor & inspections 10‑15 % of the total budget.