Skylight Kenya guide: learn how to plan rooflights and lanterns for daylight while managing flashing, drainage, heat, condensation and leaks.
Skylights in Kenya can bring natural daylight into homes, warehouses, offices and commercial buildings, while roof lanterns can create a larger architectural daylight feature. Both need careful detailing around the roof opening to prevent leaks, condensation and premature deterioration.
Adding a skylight is not simply a matter of cutting an opening and fitting a transparent panel. The roof structure, flashing, waterproofing, drainage and fixing system all need to work together.
What Are Skylights and Roof Lanterns?
A skylight is a roof-mounted opening or transparent roof element designed to admit daylight, while a roof lantern is typically a raised glazed or translucent structure installed above part of a roof.
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Skylights can be relatively compact and practical.
Roof lanterns are often larger architectural features that can provide:
- Increased daylight
- A sense of height
- Improved visual appeal
- Natural ventilation in some designs
- A distinctive architectural feature
The choice depends on the building and the amount of daylight required.
Why Install ?
Skylights can increase natural daylight in areas where conventional windows cannot provide sufficient illumination.
They can be useful in:
- Warehouses
- Workshops
- Offices
- Retail spaces
- Stairwells
- Kitchens
- Extensions
- Commercial buildings
Natural light can reduce reliance on artificial lighting during daylight hours.
Skylights in Kenya
Skylights in Kenya should be selected with local sunlight, rainfall, heat gain and roof construction in mind.
Kenyan buildings can experience strong solar exposure, meaning a skylight can introduce both useful daylight and additional heat.
Consider:
- Glazing or panel type
- Solar heat gain
- UV exposure
- Roof orientation
- Rainfall
- Roof pitch
- Ventilation
The best skylight is not necessarily the one that transmits the most light.
Roof Lantern Installation
Roof lantern installation requires accurate structural and waterproofing detailing because the lantern creates an opening and additional loads within the roof system.
Before installation, establish:
- Roof structure
- Opening dimensions
- Support requirements
- Flashing details
- Waterproofing
- Drainage
- Fixing points
- Maintenance access
The installation should follow the manufacturer's requirements and the project's structural design.
Does it Cause Roof Leaks?
A properly designed and installed skylight should not inherently cause a roof leak, but poor flashing, inadequate sealing and incorrect installation can create vulnerable points.
Common causes of skylight leaks include:
- Poor flashing
- Incorrect overlap
- Damaged seals
- Exposed fixings
- Inadequate drainage
- Incorrect roof pitch
- Poor workmanship
The interface between the skylight and roofing sheet is particularly important.
Skylight Flashing
Flashing directs rainwater away from the skylight opening and is one of the most important components of a leak-resistant installation.
Flashing should be properly integrated with the surrounding roof.
Depending on the design, details may include:
- Head flashing
- Side flashing
- Apron flashing
- Step flashing
- Counter-flashing
The exact configuration depends on the skylight and roof construction.
Rooflight Detailing
Rooflight detailing should ensure that water flowing down the roof continues around the opening without entering the building.
Good detailing considers:
- Water flow
- Roof pitch
- Sheet profile
- Overlaps
- Flashings
- Sealants
- Fixings
- Thermal movement
The rooflight should become part of the drainage plane rather than an obstruction within it.
Metal Roofs
Skylights installed in metal roofing require compatible profiles, fixings and flashing because the transparent panel must integrate with the surrounding sheets.
Check compatibility between:
- Roof profile
- Rooflight profile
- Fasteners
- Washers
- Flashings
- Sealants
A rooflight that does not match the surrounding sheet profile can be difficult to detail correctly.
Translucent Roof Panels
Translucent roof panels can provide economical daylighting across larger roof areas, particularly in warehouses, workshops and agricultural buildings.
They may be manufactured from materials such as:
- Polycarbonate
- Fibre-reinforced translucent materials
- Other purpose-designed rooflight products
Selection should consider:
- Light transmission
- UV resistance
- Impact resistance
- Weather exposure
- Expected service life
Heat Gain
A skylight can increase indoor temperatures if it admits substantial solar radiation, particularly in buildings with large areas of transparent roofing.
This can be managed through:
- Solar-control glazing
- Diffused materials
- Appropriate skylight sizing
- Shading
- Ventilation
- Insulation
The objective is to gain useful daylight without creating excessive heat.
Glare
Excessive direct sunlight can create glare that makes workspaces uncomfortable or reduces visibility on screens and equipment.
Consider skylight placement in relation to:
- Workstations
- Display areas
- Computer screens
- Seating
- Building orientation
Diffused daylight can sometimes provide more comfortable illumination than direct sunlight.
Roof Lanterns and Natural Light
Roof lanterns can create a strong source of overhead daylight because their raised geometry can capture light from multiple directions.
They can be particularly effective in:
- Atriums
- Halls
- Living spaces
- Restaurants
- Retail areas
- Extensions
However, their larger size means structural and thermal considerations become more important.
Roof Lantern Structure
A roof lantern must be supported by a structure capable of carrying the lantern's weight and transferring loads safely into the building.
Consider:
- Existing rafters
- Trusses
- Purlins
- Beams
- Opening reinforcement
- Lantern weight
- Wind forces
For an existing building, a structural assessment may be necessary before creating a large roof opening.
Wind Loading
Roof-mounted glazing and translucent panels are exposed to wind forces and should be adequately secured to the roof structure.
Wind can create:
- Uplift
- Pressure
- Movement
- Fixing stress
Edge and corner locations may be particularly exposed.
The fixing system should be selected according to the manufacturer's requirements and applicable structural design.
Rainfall
Kenyan rainfall can place significant demands on rooflight flashing and drainage details, particularly during heavy storms.
A skylight should be designed so that water is directed around the opening.
Avoid:
- Flat areas that hold water
- Poorly sealed joints
- Inadequate flashing
- Blocked drainage channels
Water should have a clear path away from the roof opening.
Condensation
Condensation can occur on the inside of skylights when warm, humid air meets a colder surface.
The risk depends on:
- Indoor humidity
- Surface temperature
- Ventilation
- Glazing properties
- Building use
Condensation may be particularly relevant in:
- Kitchens
- Workshops
- Agricultural buildings
- Industrial spaces
- Humid environments
Ventilation and appropriate glazing can help manage the problem.
Skylights and Roof Insulation
Installing a skylight creates a section of the roof with different thermal properties from the surrounding insulated roof.
The installation should therefore consider:
- Insulation continuity
- Thermal bridging
- Airtightness
- Condensation
- Frame performance
Simply installing a skylight into an insulated roof without addressing the surrounding junction can create thermal weak points.
Size
The right skylight size depends on the required daylight level, building orientation, roof design and heat-gain considerations.
Larger is not automatically better.
An oversized skylight can contribute to:
- Excessive heat
- Glare
- Higher cooling requirements
- Increased structural requirements
Daylight design should determine the appropriate size.
Positioning
Skylight positioning affects both daylight distribution and roof performance.
Consider:
- Roof orientation
- Internal room layout
- Structural members
- Roof drainage
- Solar exposure
- Maintenance access
Avoid placing a skylight where it interferes with valleys, gutters or other complicated roof details unless specifically designed for that location.
Can Skylights Be Added to Existing Roofs?
Skylights can often be retrofitted, but cutting an existing roof requires careful assessment of the roof structure and waterproofing details.
Before cutting the roof:
- Identify structural members.
- Confirm the required opening.
- Check for electrical services.
- Determine how the opening will be supported.
- Design the flashing.
- Confirm drainage.
- Install the skylight according to manufacturer instructions.
Do not cut structural roof members without appropriate professional assessment.
Roof Lantern Installation on Existing Buildings
A roof lantern retrofit may require structural reinforcement if the existing roof was not designed to support the additional opening and lantern assembly.
This is particularly important for:
- Older buildings
- Large lanterns
- Heavy glazing
- Timber roofs
- Lightweight structures
The roof should be assessed before work begins.
Choosing Glazing for Skylights
Skylight glazing should be selected according to light transmission, impact resistance, thermal performance, UV exposure and building use.
Possible options include:
- Glass
- Polycarbonate
- Acrylic
- Other specialised glazing materials
The choice depends on the project's performance requirements.
Glass vs Polycarbonate Skylights
Glass can provide excellent optical performance and durability, while polycarbonate is often valued for its lighter weight and impact resistance.
The comparison should consider:
| FactorGlassPolycarbonate | ||
| Weight | Higher | Lower |
| Impact resistance | Depends on type | Generally high |
| Optical clarity | High | Depends on product |
| Structural requirements | Greater | Often lower |
| Thermal performance | Product dependent | Product dependent |
| Cost | Product dependent | Product dependent |
Always compare the actual manufacturer's specifications rather than assuming every product performs the same way.
Skylight Maintenance
Regular skylight maintenance helps preserve daylight transmission and identify leaks before they cause extensive damage.
Inspect for:
- Cracks
- Discolouration
- Loose fixings
- Failed seals
- Damaged flashing
- Dirt accumulation
- Corrosion
Clean skylights using methods compatible with the glazing material.
Roof Lantern Maintenance
Roof lanterns require periodic inspection because their frames, glazing, seals and drainage details are exposed to weather.
Check:
- Frame joints
- Glazing
- Flashings
- Sealants
- Drainage
- Fixings
- Condensation
Maintenance access should be considered during the original design.
Common Skylight Installation Mistakes
Most skylight problems occur at the junction between the roof and the skylight rather than in the transparent panel itself.
Common mistakes include:
Poor Flashing
Incorrect flashing can allow water into the roof assembly.
Wrong Fixings
Incompatible fasteners can cause corrosion or leaks.
Over-Reliance on Sealant
Sealant should complement proper flashing rather than replace it.
Cutting Structural Members
Removing rafters or purlins without reinforcement can compromise the roof.
Ignoring Heat Gain
Large skylights can make interiors excessively hot.
Poor Maintenance Access
Rooflights eventually need cleaning and inspection.
Skylight and Roof Lantern Checklist
Use this checklist before purchasing or installing a rooflight or roof lantern.
- Roof structure assessed
- Opening dimensions confirmed
- Skylight type selected
- Glazing/material specified
- Roof pitch checked
- Flashing detail established
- Fixing system specified
- Waterproofing planned
- Drainage considered
- Wind exposure assessed
- Heat gain considered
- Condensation considered
- Insulation junction detailed
- Maintenance access provided
Final Thoughts
Skylights in Kenya can improve natural daylight, but their success depends on proper structural support, flashing, drainage, waterproofing and thermal detailing. Roof lanterns offer an architectural daylight solution but require even greater attention to structure and weatherproofing because of their size and complexity.
The key principle is simple:
Bring daylight in without creating a new weak point in the roof.
Before installing a skylight or roof lantern, coordinate:
Structure + glazing + flashing + drainage + insulation + ventilation + maintenance
Proper detailing at the roof opening is what separates a useful daylight feature from a future leak problem.
Contact Us
If you are planning skylights in Kenya, rooflights or commercial roofing modifications, our team can help you compare suitable roofing materials, profiles and accessories for your project.
Visit Us:
Funzi Road Branch, End of Funzi Road, Industrial Area
Ali Glaziers LTD Building
Nairobi, Kenya
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+254 (0) 716 259 682
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