Patio & Paving Calculator
Plan your layout with accurate slab counts and bedding material estimates.
Patio Estimate
Ordering Tip:
Always order a few extra slabs. Natural stone and porcelain can vary in shade between batches, making it difficult to match if you run out.
Professional Paving Guide: Layouts, Materials & Ratios
Planning Your Patio Layout
A successful patio starts with a solid plan. Choosing between natural sandstone, limestone, or modern porcelain slabs will dictate not only the look but also the installation method and total cost.
In the UK, 600mm x 600mm and 450mm x 450mm are the most common sizes, but many homeowners now opt for "Random Pattern" kits which use multiple sizes for a traditional look.
Standard UK Slab Sizes
- 600mm x 600mm (0.36m²)
- 900mm x 600mm (0.54m²)
- 450mm x 450mm (0.20m²)
- 300mm x 300mm (0.09m²)
The Importance of a "Full Bed"
Many amateur installers use the "spot bedding" technique (putting a blob of mortar in each corner). This is a mistake. In the UK, water will collect in the voids beneath the slab. In winter, this water freezes and expands, popping the slab loose.
A full wet bed of 1 part cement to 4 parts sharp sand ensures the slab is supported across its entire surface, preventing movement and weed growth.
Natural Stone vs Porcelain
Natural Stone: Requires sealing, varies in thickness, easier to lay on a standard mortar bed.
Porcelain: Extremely durable, non-porous, requires a "priming slurry" (SBR) on the back of each tile to ensure it bonds to the mortar.
Jointing (Pointing)
Once laid, the gaps (joints) need filling. Traditional sand/cement pointing is common, but modern "brush-in" jointing compounds (like EasyJoint) are faster and allow for water permeability, which helps with drainage.
Pro Tip: The "Fall"
Never build a patio perfectly flat! It must have a slight slope (a "fall") away from your house to ensure rainwater drains off and doesn't pool against your walls or cause damp issues. A fall of 1 in 60 (1cm drop for every 60cm of length) is ideal.
Patio Construction & Planning FAQ
Installation Disclaimer
This calculator provides an estimate based on square areas. Complex shapes, circles, or diagonal patterns will require significantly more wastage. Always check your site measurements twice before ordering expensive paving materials.