Modern Portland cement acts like a plastic bag over the wall. Water gets in through cracks but cannot evaporate. When winter comes, that trapped water freezes, expands, and blows the face off the stone (spalling).
| Stone Type | Recommended CMP Product | Rationale | | :--- | :--- | :--- | | | CMP NHL 3.5 (White) | Limestone is soft. Hard cement crushes it. NHL is sacrificial. | | Sandstone (Red/Buff) | CMP Weatherstruck (Buff) | Sandstone needs a rough, sandy texture to bond mechanically. | | Granite / Basalt | CMP High Strength (Class II) | Dense stone requires a high compressive strength (over 15N/mm²). | | Reconstructed / Cast Stone | CMP Re-Con Match | Specifically pigmented to match factory-made cast stone. | The Technical Advantage: Understanding "Permeability" If you ask any conservation officer what they look for in CMP stonemason supplies , they will say "permeability." cmp stonemason supplies
A: You don't match the stone; you match the mortar . Use CMP’s "Color Match" service. You send them a sample of your old mortar (a 50g chip), and they will dye a custom batch of CMP pre-mix to match exactly. The Future of Masonry As building regulations tighten regarding thermal efficiency , the natural stone industry faces a paradox: insulating a stone wall with foam kills the stone. CMP stonemason supplies is currently leading research into breathable insulation —lime-hemp mortars that offer an R-value (thermal resistance) without trapping moisture. Modern Portland cement acts like a plastic bag over the wall
In the demanding world of stone masonry, the difference between a masterpiece and a mediocre build often comes down to the tools and materials used. For professionals across the UK and beyond, one name has consistently stood as a benchmark for reliability and performance: CMP Stonemason Supplies . | Stone Type | Recommended CMP Product |
For technical data sheets and safety data sheets (SDS), always consult the official CMP product literature before starting a heritage or structural project.
Don't let a beautiful stone wall be ruined by a bag of cheap, stiff cement. Invest in CMP, invest in the right technique, and watch your masonry work weather gracefully for decades.