Flat Roof Cost Calculator

Working out how much it costs for a new flat roof is now even easier than you think when you use our Flat Roof Calculator!

Let’s get started 1st steps for using our Flat Roof Cost Calculator

• Using advanced technology Composite Roof Supplies has provided an easy 3-step solution for working out what you need and how much a GRP Roof Kit will cost.

All you need to know is the Size of your roof! It’s as simple as that, no experience is required.

Step 1: First off enter the roof Length x Width: *Enter the length and width in either Metric or imperial measurements. enter these details using our Flat Roof Cost Calculator

Tip:  did you know if you have an L-shaped roof create 2 separate kits and just treat them as a square and a rectangle?

Step 2: Understand the Roof edges:  Fibreglass edge trims are really important when the Grp is laid into position, the pre-formed edge trim creates not only a nice finish but ensures water can run off the roof into any gutters or prevent water run off in sections where water must be contained. add the trims that best suit your spec.

Note: If you have trims already select no trim required.

The kit builder uses standard-size trims. seen in the section below

Fibreglass Trims Glossary

Kit builder Trim sizes:

• A200 drip trim – The mid-size of the drip trims, the sizes are Length 3m – Drop 90mm – Flange > 80mm – Roll 10mm Compatible with the B260 raised edge trim
• B260 raised edge trim– The mid-size raised edge trim, the sizes are: Length 3m – Visible face 125mm – Flange > 100mm – Roll 10mm
• Wall Edge – universal and has a flange of 100mm or 75mm – overall visible sections – 100mm x 25mm x 75mm – Overall height up the wall from the deck boards 125mm or 95mm
• Flat Slope Trim – 300mm flat trim supplies rolled up to 20metre pieces
• Parapet Edges – 75mm x 105mm – internal or external
• Expansion Trim – used on roofs over 50m2 or to join to roofs together like a felt garage and a new GRP Roof

Tip: you can add additional trims or slightly different size trims within the shop section of the website here

Fiberglass trims come in 3 different sizes. The sizes below are excluded from the Flat Roof Calculator but can be purchased separately

• A170 drip trim – The smallest size of the dedicated drip trims, the dimensions are: Length 3m – Drop 65mm – Flange > 80mm – Roll 10mm – Compatible with the B230 raised edge trim
• B230 raised edge trim – The smallest of the dedicated raised edge trims, the dimensions are Length 3m – Visible face 105mm – Flange > 100mm – Roll 10mm
• A250 drip trim – The largest of the drip trims, the dimensions are: Length 3m – Drop 140mm – Flange > 80mm – Roll 10mm – Compatible with the B300 raised edge trim
• B300 raised edge trim– The largest of the raised edge trims, the dimensions are Length 3m – Visible face 175mm – Flange > 100mm – Roll 15mm

Step 3: Congratulations your GRP Kit is complete! you can add extras in the last step such as:

Premium 600gsm Chopped Strand Matting
Upgrade from the standard 450gsm (Includes extra Resin and Hardener)

Pre-formed Corners
Upgrade to pre-formed corners rather than fabricating your own with a bandage. Includes 2x C1 External Corner

Anti-Slip Grit For Balconies
Added to create a non-slip topcoat

GRP Installation Tool Kit
Everything you’ll need to fit your kit! Dispenser Bottle, Paddle Rollers, Roller Sets with Extending Poles, Buckets, Paint Brushes, and Disposable Gloves

Why not try our EPDM Flat Roof Cost Calculator?

Efficient Material Calculation for a 25m² EPDM Roofing Project

When embarking on an EPDM roofing project for a 25m² area, accurate material calculation is crucial for a successful and cost-effective installation. EPDM (Ethylene Propylene Diene Monomer) roofing products are renowned for their durability and weather resistance, making them an excellent choice for various roofing applications.

Step 1: Measure the Roof Area easy Flat Roof Cost Calculator with our kit builder

Begin by measuring the roof’s surface area in square meters. For a 25m² roof, this step is straightforward, but ensure precise measurements to avoid material wastage.

Step 2: Flat Roof Cost Calculator using EPDM Membrane

EPDM roofing membranes typically come in rolls of varying widths, commonly 3.05m or 6.10m. Calculate the number of rolls needed by dividing the total roof area by the width of the chosen EPDM membrane.

Number of Rolls=Total Roof AreaEPDM Membrane WidthNumber of Rolls=EPDM Membrane WidthTotal Roof Area​

Round up to the nearest whole number to ensure complete coverage. Consider adding a percentage for overlaps and cut-offs during installation.

Step 3: Adhesive and Seam Tape Calculation

EPDM roofs require adhesives and seam tapes for proper installation. The amount needed depends on the membrane seams and the bonding method. As a general rule, estimate the adhesive and seam tape quantities based on the linear meters of seams.

Step 4: Edge Trim and Sealant Calculation

Calculate the linear meters of edge trim needed for finishing and protecting the roof edges. Additionally, consider the amount of sealant required for any joints, corners, or flashing details.

Step 5: Insulation and Substrate Preparation

If insulation or additional substrate materials are required, calculate the quantity based on the roof’s dimensions. Ensure that the substrate is smooth, clean, and properly prepared to enhance the EPDM roofing system’s performance.

Step 6: Consultation with Suppliers

Engage with reputable EPDM roofing material suppliers for precise product specifications and recommendations based on your project’s specific requirements. They can provide insights into product variations, adhesive types, and accessories needed for a seamless installation.

By carefully calculating the materials required for your 25m² EPDM roofing project, you not only ensure efficient resource utilization but also contribute to the overall success and longevity of the roofing system. Professional advice and quality products from trusted suppliers will further enhance the durability and performance of your EPDM roof.

Here are some Q&A pairs related to EPDM roofing:

Q1: What is EPDM roofing? A1: EPDM roofing stands for Ethylene Propylene Diene Monomer, a type of synthetic rubber roofing membrane known for its durability and resistance to weathering.

Q2: Why choose EPDM roofing for a project? A2: EPDM roofing is chosen for its exceptional durability, flexibility, and resistance to UV radiation. It provides a long-lasting and cost-effective solution for various roofing applications.

Q3: How is EPDM roofing installed? A3: EPDM roofing is typically installed using adhesive or mechanically attached systems. The sheets are laid out and secured, and seams are sealed to create a watertight barrier.

Q4: What are the advantages of EPDM roofing? A4: EPDM roofing offers advantages such as excellent weather resistance, longevity, ease of installation, and low maintenance requirements. It is also environmentally friendly and recyclable.

Q5: How do I calculate the materials needed for an EPDM roofing project? A5: To calculate materials, measure the roof area, determine the EPDM membrane width, and calculate the number of rolls needed. Consider additional materials like adhesives, seam tapes, edge trim, and sealant based on project specifics.

Q6: Can EPDM roofing be used in different climates? A6: Yes, EPDM roofing is suitable for various climates. It performs well in extreme temperatures, remains flexible in cold conditions, and resists damage from UV exposure.

Q7: Are EPDM roofs environmentally friendly? A7: Yes, EPDM roofing is considered environmentally friendly. The material is recyclable, and its long lifespan reduces the need for frequent replacements, contributing to sustainability in construction.

Q8: How do I maintain an EPDM roof? A8: EPDM roofs require minimal maintenance. Regular inspections for damage, cleaning debris, and addressing issues promptly can help prolong the roof’s lifespan.

Q9: Can EPDM roofing be repaired if damaged? A9: Yes, EPDM roofs are repairable. Small punctures or tears can be patched using EPDM repair kits. For larger damages, it’s advisable to consult a roofing professional.

Q10: Where can I purchase EPDM roofing materials? A10: EPDM roofing materials are available from various roofing suppliers and home improvement stores. It’s recommended to buy from reputable suppliers to ensure product quality.