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---
name: taipei-building-decorative-structures
description: "This skill should be used when reviewing Taipei City facade design (臺北市新建案立面檢討/外牆立面規畫), building attached non-structural decorative elements (外牆附置物/裝飾物/附屬物), frames, beams, columns, panels, louvers, railings, canopy/balcony/terrace/facade decorative features in Taipei City per the 2024 Taipei City Building Attached Decorative Structure Design Exemplar Compilation (臺北市建築物附置裝飾性構造物設計範例彙編, Effective 2024-09-25). Includes porosity, projection, emergency opening, building area, FAR exemption, and height-slope restriction review."
license: CC-BY-SA-4.0
compatibility: claude-code,opencode,agent-skills
metadata:
audience: architects
region: taiwan
class: C
status: verified
data-currency: "2026-07-28"
---
# Taipei City Building Attached Decorative Structures Review
## Overview
This skill provides step-by-step compliance evaluation for non-structural decorative elements attached to building facades, balconies, terraces, canopies, roof structures, and main entrances in Taipei City.
Effective **September 25, 2024** (Doc No. 北市都授建字第 1136163958 號 / 113年度彙編第045號編號第016號), this regulation replaces and repeals Section IV of the 2017 Taipei Building Permit Sample Inspection Resolution Compilation (106年9月6日北市都授建字第10634955700號函).
---
## Interactive Web Tool & Visualization (互動檢討網頁與全套圖例)
When responding to queries regarding Taipei City facade design, building attached decorative structures, louvers, fins, or balcony/terrace regulations, **ALWAYS include the link to the interactive calculation webpage**:
- **Interactive Calculation & Blueprint Webpage**: [臺北市建築物附置裝飾性構造物互動檢討與全套圖例系統](../index.html) (`../index.html`)
---
## Scope & Non-Combustibility Requirement
- **Definition**: Non-structural decorative frames, beams, columns, panels, railings, louvers/shutters attached to the exterior of buildings or miscellaneous structures.
- **Material Mandate**: All decorative elements **MUST be constructed of non-combustible materials (不燃材料)**.
---
## Quantitative Review Rules by Element Type
### 1. Balcony Decorative Structures (陽台裝飾物)
| Check Item | Threshold / Limit | Area & Height/Rear Yard Restriction |
| :--- | :--- | :--- |
| **Porosity Rate (透空率)** | $\ge 2/3$ (excluding railing height) | N/A |
| **Emergency Opening (緊急開口)** | At least 1 per unit: Rectangular $\ge 75\text{ cm} \times 1.2\text{ m}$ OR Circular $\varnothing \ge 1.0\text{ m}$ | Must be un-obscured |
| **L-shaped / Multi-fold Balcony Columns/Panels** | Combined width $\le \frac{1}{3} L_{\text{balcony}}$ (excluding structural column width) | Exceeding 1/3 is prohibited |
| **Piping Enclosure Porosity** | $\ge 1/2$ | Enclosed area is included in balcony area |
| **Balcony Sunshade / Canopy Exceeding 2m** | Porosity $\ge 1/2$. Total depth (balcony + sunshade) $> 2.0\text{ m}$ | Portion exceeding 2.0m **MUST BE INCLUDED** in Building Area & FAR, subject to Height-Slope & Rear Yard rules |
| **Balcony / Entrance Canopy Overlap** | Overlapped area evaluated under balcony rules | If evaluated as canopy, cannot name room or register title |
### 2. Terrace Decorative Structures (露台裝飾物)
- **Height Limit**: Must not exceed the height of the current floor (當層為限).
- **Porosity Rate**: $\ge 1/2$ (calculated on remaining area above railing height).
- **Extension Limits**:
- Inward extension from railing centerline: $D_1 \le 50\text{ cm}$.
- Outward extension from railing centerline: $D_2 \le 1.0\text{ m}$.
### 3. Canopy Decorative Structures (雨遮裝飾物)
- **Maximum Canopy Depth**: $\le 1.0\text{ m}$.
- **Decorative Railing Height**: $\le 90\text{ cm}$.
- **Decorative Louver Porosity**: $\ge 2/3$.
- **Emergency Entry Opening**: Must provide at least 1 emergency entry ($\ge 75\text{ cm} \times 1.2\text{ m}$ or $\varnothing \ge 1.0\text{ m}$).
- **Window Sill Height Rule**: Exterior wall window sills behind decorative railings/louvers must be $> 1.2\text{ m}$ high or equipped with fixed windows (固定窗).
### 4. Exterior Wall Facade Decorative Structures (外牆裝飾物)
| Sub-type | Dimension & Porosity Rules | Building Area & FAR Treatment |
| :--- | :--- | :--- |
| **Enclosing Louvers / Perforated Panels** | Outward projection $\le 2.0\text{ m}$ from wall centerline; Porosity $\ge 2/3$ | Projected area (incl. horizontal ties) **INCLUDED in Building Area** & subject to Height/Rear Yard rules |
| **Horizontal / Vertical Fins & Plates** | Projection $\le 2.0\text{ m}$ from wall centerline | Portion $\le 1.0\text{ m}$: **EXEMPT from Building Area**. Portion $> 1.0\text{ m}$ up to $2.0\text{ m}$: **INCLUDED in Building Area** & subject to Height/Rear Yard rules |
| **Enclosed Fin + Louver / Glass Combo** | Must meet Porosity $\ge 2/3$ | Projected area (incl. panels & ties) **INCLUDED in Building Area** |
| **Solid Decorative Columns / Panels** | Solid filled, width $< 1.5\text{ m}$ | **EXEMPT from Floor Area**. Clear gap between continuous columns $\ge 1.5\text{ m}$. Columns on structural column sides: combined width $\le 1.5\text{ m}$ (no openings allowed) |
| **Wall Centerline Determination** | Hollow interior: measured to outer wall centerline. Solid interior: measured to volumetric center $(d_1-d_2)/2$ | Used for exact dimension and setback calculations |
### 5. Structural Spandrel / Structural Beams (結構性過樑)
- **Max Outward Projection**: $\le 10\text{ cm}$ from beam outer edge.
- **Porosity Requirement**: $\ge 2/3$.
- **Area & Height Limits**: **MUST BE INCLUDED in Building Area**, subject to Height-Slope & Rear Yard rules.
### 6. Perimeter Wall Gate Openings (圍牆出入口)
- **Depth Limit**: $\le 2.0\text{ m}$.
- **Lateral Extension**: $\le 1.0\text{ m}$ outwards from gate sides.
- **Prohibitions**: Cannot cross building line (建築線), cannot connect to building or other decorative features.
### 7. Roof Level & Roof Appurtenances (屋頂層及屋突)
- **Night Lighting Systems ($\le 2.0\text{ m}$)**: Evaluated per Building Technical Regulations Art. 1-10-3 (露天機電設備); **EXEMPT** from roof appurtenances height & area.
- **Roof Appurtenances Horizontal Fin ($\le 50\text{ cm}$)**: Projections $\le 50\text{ cm}$ from wall centerline are **EXEMPT** from the 1/8 roof appurtenance area cap.
- **Roof Appurtenances Projections ($> 50\text{ cm}$)**: Deduct 50 cm from outer edge to set the evaluation centerline for 1/8 roof appurtenance area; if directly projecting to ground, projected area **INCLUDED in Building Area** & subject to Height/Rear Yard rules.
### 8. Main Entrance Canopies & Decorative Portals (出入口雨遮與造型框架)
1. **1F Main Entrance Canopies**: Canopy depth $\le 2.0\text{ m}$ extended on left/right sides.
2. **Entrance Decorative Portals / Frames**:
- Projected Area: **INCLUDED in Building Area** & subject to Height/Rear Yard rules.
- Enclosed Volume / Coverage: Must be $< 30\%$ of maximum allowable Building Area (設計建蔽率 30%).
- Porosity: $\ge 2/3$ open; **NO TOP COVER (無頂蓋)** allowed on porous parts.
- Legal Requirement: Developer affidavit (起造人切結), incorporated into condominium rules (規約草約), drawing notes, and property transfer documents.
---
## Discretionary Pre-Review Process (預審機制)
If a project cannot comply with this compilation due to special functional needs, structural uniqueness, or environmental/landscape requirements:
- The project may submit an application to the **Taipei Building Permit Pre-Review Committee (臺北市建造執照預審小組)** for approval of partial or full exemption.
---
## Checklist for Plan Reviewers & Architects
- [ ] Are all decorative materials non-combustible?
- [ ] Balcony openings: Is porosity $\ge 2/3$? Is an emergency opening ($\ge 75 \times 120\text{ cm}$ or $\varnothing \ge 100\text{ cm}$) reserved?
- [ ] Balcony sunshade total depth: Does it exceed 2.0m? If yes, is the excess included in FAR & Building Area?
- [ ] Exterior wall fins: Is the projection $\le 1.0\text{ m}$ for building area exemption? If between $1.0\text{ m}$ and $2.0\text{ m}$, is it included in Building Area?
- [ ] Exterior wall solid columns: Is width $< 1.5\text{ m}$ with net spacing $\ge 1.5\text{ m}$?
- [ ] Entrance portal frame: Is enclosed area $< 30\%$ of building area? Is porosity $\ge 2/3$? Is no-top-cover affidavit prepared?
---
## Worked Examples
### Example 1: Balcony Decorative Sunshade & Column Review
```text
Inputs:
L_balcony = 6.0 m (Balcony length)
D_balcony = 1.5 m (Balcony depth)
D_sunshade = 0.8 m (Decorative sunshade projection beyond balcony outer edge)
Sunshade Porosity = 60% (3/5)
Emergency Opening = 80 cm (W) x 130 cm (H)
Decorative Column Width = 1.2 m
Evaluation & Rules Applied:
1. Material: Non-combustible (Compliant).
2. Emergency Opening: 80 cm >= 75 cm AND 130 cm >= 120 cm (Compliant).
3. Decorative Column Width: 1.2 m <= (1/3)*6.0 m = 2.0 m (Compliant).
4. Sunshade Porosity: 60% >= 50% (Compliant per Section 1.5).
5. Combined Projection & Area Treatment:
Total Depth D_total = 1.5 m + 0.8 m = 2.3 m > 2.0 m.
Excess Depth = 2.3 m - 2.0 m = 0.3 m.
Excess Area to Include = 6.0 m x 0.3 m = 1.80 m²
Result:
- Balcony Structure: PASS.
- Action Required: Include 1.80 m² in Building Area and Floor Area Ratio (FAR) calculation, and verify 3.6:1 height-slope restriction.
```
### Example 2: Exterior Wall Facade Vertical Solid Fins & Enclosing Louver Panel Review
```text
Inputs:
Wall Length = 12.0 m
Type A (Solid Vertical Fin):
Outward Projection = 0.8 m
Fin Solid Width = 0.4 m
Net Spacing between Fins = 1.8 m
Type B (Enclosing Louver Panel):
Outward Projection = 1.5 m
Louver Porosity = 70% (7/10)
Evaluation & Rules Applied:
1. Type A Solid Fin:
Projection 0.8 m <= 1.0 m, Solid Width 0.4 m < 1.5 m, Net Spacing 1.8 m >= 1.5 m.
Rule: Projection <= 1.0 m and solid width < 1.5 m -> EXEMPT from Building Area.
2. Type B Enclosing Louver Panel:
Projection 1.5 m <= 2.0 m, Porosity 70% >= 2/3 (66.7%).
Rule: Projection > 1.0 m up to 2.0 m for enclosing louvers -> Projected Area INCLUDED in Building Area.
Projected Area to Include = 12.0 m x 1.5 m = 18.00 m²
Result:
- Type A Fins: EXEMPT from Building Area & FAR.
- Type B Panel: PASS conditionally (Must include 18.00 m² in Building Area & verify Height/Rear Yard setback).
```
---
## Related Skills
* [height-ratio-front-road-review](../../../../建築技術規則/建築設計施工編/高度比與面前道路認定/height-ratio-front-road-review/SKILL.md)
* [floor-area-exemption-pitfalls](../../../../容積率與建蔽率計算/容積免計實務陷阱/floor-area-exemption-pitfalls/SKILL.md)
* [balcony-lobby-far-recalculation](../../../../容積率與建蔽率計算/陽臺梯廳回計容積計算/balcony-lobby-far-recalculation/SKILL.md)