DIY Renovation

DIY Bathroom Renovation Step by Step

Bathroom renovation is among the most technically demanding DIY projects in Czech homes. The combination of waterproofing, tiling, plumbing connections and electrical work in a confined, moisture-heavy space requires careful sequencing. This article follows the logical order of operations — from stripping out the old bathroom to the final grouting — and highlights the specific regulatory requirements that apply to Czech residential construction.

Phase 1 — Assessment and Planning

Before any demolition, document the existing layout with photographs and measurements. In Czech panel apartment buildings (panelák), the structural walls and load-bearing elements are fixed. Non-structural partition walls — typically made of lightweight concrete blocks or gypsum board — can be repositioned, but any change to a wet area (expanding the bathroom footprint, for instance) requires notification to the local building authority (stavební úřad) under Act No. 283/2021 Coll. (the new Czech Building Act).

Check for asbestos-containing materials in older buildings constructed before 1991. Tiles, adhesives, insulation boards and vinyl floor coverings from that era may contain asbestos. If in doubt, commission a certified asbestos survey before proceeding. Removal of asbestos-containing materials must be carried out by a licensed contractor.

Key Measurements

• Floor area — for waterproofing membrane and tile quantities (add 10–15% for cuts and waste)
• Wall area — separate calculations for wet zone (shower/bath surround) and dry zone
• Drain position — critical for establishing minimum floor fall gradient (typically 1–2%)
• Pipe centres — for shower valve, taps and WC connection

Phase 2 — Strip-Out

Ceramic tile removal in Czech bathrooms typically involves three layers: the glaze, the tile body and the bed mortar beneath. A rotary hammer drill set to chisel mode with a wide chisel attachment removes tiles from concrete substrates efficiently. For tiles on gypsum board (sádrokarton), use a lower-impact method — vibration transfers to the board fixings and can loosen them from the studwork.

Surface preparation is critical before waterproofing. Residual adhesive must be ground flush or the membrane will not bond correctly.

After tile removal, grind the substrate flat using an angle grinder with a cup wheel attachment. Residual adhesive raised more than 2–3 mm above the substrate level will create high spots that show through the new tile layer. The floor drain should be sealed temporarily to prevent debris from entering the soil stack.

Phase 3 — Waterproofing

Czech standard ČSN 73 3610 specifies requirements for waterproofing in wet areas. The minimum specification for a shower enclosure or bath surround is a flexible waterproofing membrane applied in two coats, covering the full floor area and extending up the walls by at least 200 mm (300 mm preferred in shower enclosures). Corners and junctions between floor and wall must be reinforced with waterproofing tape embedded in the first coat of membrane.

Cementitious waterproofing membranes (e.g. products from Mapei, Schönox or Rako) are widely available through Czech builder's merchants and perform well in the Czech humidity cycle. Allow full cure time per the manufacturer's datasheets before applying adhesive — typically 24 hours per coat in conditions above 15°C.

Phase 4 — Floor Preparation and Tiling

Floor tiles in wet areas require a fall toward the drain — typically 1–2% gradient. In renovation projects where the existing screed is level, a self-levelling compound with added slope (achieved by feathering compound thickness across the floor) is the practical approach. Allow the compound to fully harden before tiling.

Tile adhesive selection depends on substrate. For concrete or screed substrates, a C2TE-classified adhesive (flexible, extended open time) is the minimum specification in wet areas. For gypsum board substrates, use adhesive rated as non-water-softening. In Czech renovation trade practice, epoxy adhesives are used for natural stone and large-format tiles (600×600 mm or larger) where greater bond strength is required.

Wall finishing after tiling. In Czech bathrooms, the junction between tiled and painted surfaces requires a silicone movement joint, not grout.

Grout Selection

For joints narrower than 6 mm in wet areas, an epoxy grout (Class RG per EN 13888) provides superior stain and moisture resistance compared to cementitious grout. For larger joints, a flexible sanded grout classified as CG2 or higher is appropriate. Silicone sealant — not grout — should be used at internal corners and at junctions between tiles and sanitaryware.

Phase 5 — Plumbing Connections

In Czech Republic, plumbing work on internal water supply systems does not strictly require a licensed plumber for the physical connection, but connecting to the building's soil stack or making changes to the cold/hot water risers in apartment buildings typically requires written consent from the building management (správce budovy) and must comply with ČSN EN 12056 for gravity drainage systems.

Compression fittings and push-fit connections (popular brands: Herz, Giacomini, Uponor) are used for copper, CPVC and PEX pipework. All connections behind walls or under floors must be accessible or must use leak-free joint types — soldered copper joints or press-fit connections are the standard choices for concealed runs.

Phase 6 — Electrical Work in the Bathroom

Czech and EU regulations (ČSN 33 2000-7-701, based on IEC 60364-7-701) define four protection zones in bathrooms. Zone 0 (inside the bath/shower) allows only SELV (Safety Extra-Low Voltage) equipment rated IPX7. Zone 1 (above bath/shower to 2.25 m height) allows IPX4 or higher. Zone 2 (extending 0.6 m beyond the bath/shower rim) requires IPX4 minimum. All electrical work in zones 0–2 must be carried out or certified by a licensed electrician (revizní technik) holding the ČSN 33 2000 authorisation.

Underfloor heating in bathrooms is covered by the same zoning rules. Resistive heating mats below tiles are the most common approach in Czech renovations and must be connected via a ground-fault circuit interrupter (proudový chránič, 30 mA).

Typical Timeline for a Standard Czech Bathroom (4–6 m²)

1. Strip-out and disposal: 1–2 days
2. Surface preparation and substrate repair: 1 day
3. Waterproofing (two coats + cure): 2–3 days
4. Floor and wall tiling: 2–3 days
5. Grout cure: 1 day
6. Sanitaryware installation: 1 day
7. Electrical connections and commissioning: 1 day (licensed electrician)

Total elapsed time, working on weekends: approximately 4–6 weekends depending on drying and cure periods. Material costs for a mid-range finish (mid-grade ceramic tiles, standard sanitaryware) in Prague 2026: approximately 35,000–60,000 CZK depending on area and specification.

References: TZB-info (Czech technical building portal) · Czech Ministry for Regional Development — Building Act