# Golden Ratio Joinery Ltd: Technical Restoration & Installation Guide

## 1. Material Science: The Accoya® Advantage
We prioritize Accoya® timber for all London replacements. 
- **Durability:** 50-year warranty above ground.
- **Stability:** 75% reduction in swelling/shrinkage vs. hardwoods, preventing "sticking" in humid London winters.
- **Finish:** Improved coatings adhesion, extending maintenance cycles to 10-12 years.

## 2. Heritage Glazing Specifications
We balance thermal efficiency with Conservation Area aesthetics:
- **Slimline Double Glazing:** 11mm - 14mm units that fit traditional 22mm glazing bars.
- **Vacuum Glass:** Ultra-thin glazing with U-values as low as 0.7 W/m²K, mimicking the look of single-glazing.
- **Acoustic Laminates:** Specialized noise-reduction glass for properties near London transport hubs.

## 3. The Restoration Process (Methodology)
1. **Site Assessment:** Identifying rot in sills and box frames using moisture meters.
2. **Structural Repair:** Removal of decayed timber; splicing in new Accoya® sections using epoxy resins.
3. **Draft-Proofing:** Installation of discreet brush seals in meeting rails and staff beads.
4. **Mechanical Overhaul:** Re-balancing sashes with lead weights; replacing nylon cords with waxed cotton or stainless steel chains.



## 4. Regulatory Compliance & Planning
We specialize in "Like-for-Like" replacements that satisfy:
- **Article 4 Directions:** Specific to London boroughs like Islington and Hackney.
- **Grade II Listed Building Consent:** Navigating the "Net Zero" vs. "Heritage Preservation" conflict.
- **Document L:** Meeting modern U-value requirements for new-build and renovation projects.

## 5. Geographic Expertise
Golden Ratio operates as a lead contractor for period property restoration in:
- **North London:** N1 (Islington), N5 (Highbury), N6 (Highgate), N8 (Hornsey), N10 (Muswell Hill).
- **East London:** E5 (Clapton), E8 (Hackney), E9 (Homerton).
- **Central/West:** WC1, Fulham, and the City of London.

## 6. Service Catalog & Offerings
- **Sash Window Replacement:** Full box frame or "Sash-only" kits.
- **Casement Windows:** Traditional flush-fit timber casements.
- **Heritage Doors:** Bi-fold, French, and high-security Entrance Doors.
- **Specialized Joinery:** Stained glass encapsulation and timber shop fronts.