Is Non Shrink Grout Waterproof?
Non shrink grout is widely used for structural and load-bearing applications, but a common question on site is whether non shrink grout is waterproof. Understanding its water resistance properties helps engineers and contractors decide when it is suitable on its own and when additional waterproofing systems are required.
What Does Waterproof Mean in Construction?
In construction terms, waterproof means the ability of a material to completely prevent water penetration under pressure. Waterproof materials form a continuous barrier that blocks water movement, even in wet or submerged conditions.
- Waterproof materials stop water completely
- Water-resistant materials slow down water penetration
- Structural materials may resist moisture but still allow seepage
Is Non Shrink Grout Fully Waterproof?
Non shrink grout is not fully waterproof. It is best described as water-resistant rather than waterproof.
- Dense cementitious structure limits water penetration
- Resists moisture ingress better than ordinary cement grout
- Does not act as a waterproof membrane
While it performs well in damp environments, it should not be relied upon as the sole waterproofing solution.
Why Non Shrink Grout Resists Water
Non shrink grout has better water resistance due to its formulation.
- Low permeability when mixed correctly
- Dense packing of graded aggregates
- Reduced micro-voids compared to ordinary grout
- Controlled expansion ensures tight contact with substrates
These properties reduce pathways for water movement but do not completely block water under pressure.
Where Non Shrink Grout Performs Well Against Moisture
Non shrink grout is suitable in areas exposed to occasional moisture.
- Machinery base plates in damp environments
- Column bases in covered structures
- Anchor bolt pockets exposed to humidity
- General structural grouting with limited water exposure
Where Non Shrink Grout Is Not Sufficient Alone
In areas with continuous or pressurised water exposure, additional protection is required.
- Water tanks and reservoirs
- Basements with groundwater pressure
- Submerged foundations
- Areas exposed to constant water flow
In such cases, non shrink grout must be combined with waterproofing systems.
How to Improve Water Resistance of Non Shrink Grout
Water resistance can be enhanced through proper practices.
- Use correct water-to-grout mixing ratio
- Ensure complete compaction and void-free placement
- Apply proper curing to reduce surface porosity
- Seal exposed grout surfaces if required
Non Shrink Grout vs Waterproof Grout
Understanding the difference helps in material selection.
- Non shrink grout focuses on load transfer and dimensional stability
- Waterproof grout focuses on blocking water movement
- Both serve different purposes and are not interchangeable
Common Site Misconception
A frequent mistake is assuming non shrink grout can replace waterproofing.
- Leads to leakage issues in wet areas
- Causes premature repairs and rework
- Results from misunderstanding material function
Best Practice Recommendation
For best performance, use non shrink grout and waterproofing together where needed.
- Use non shrink grout for strength and stability
- Apply waterproof coatings or membranes separately
- Follow project specifications strictly
Frequently Asked Questions (FAQ)
1. Can non shrink grout stop water leakage?
It can reduce seepage but cannot stop pressurised water completely.
2. Is non shrink grout suitable for water tanks?
No, it must be combined with a proper waterproofing system.
3. Does curing affect water resistance?
Yes, proper curing significantly improves density and resistance.
4. Can sealers be applied over non shrink grout?
Yes, surface sealers can improve water resistance.
5. Is non shrink grout better than cement grout in wet areas?
Yes, it performs better but is still not fully waterproof.
Raltro
Raltro is a construction materials knowledge platform focused on clarifying real-world performance expectations of building materials. By explaining the difference between water resistance and waterproofing, and where non shrink grout fits within this distinction, Raltro helps professionals choose the right combination of materials to achieve both structural stability and effective moisture protection without costly site mistakes.