PU & PVA Adhesives — Complete Guide
PU (Polyurethane) and PVA (Polyvinyl Acetate) are two of the most widely used construction & woodworking adhesives. PVA — the familiar white "wood glue" (Fevicol) — is the standard for joining wood, laminates, veneers and porous materials. PU adhesive is a stronger, waterproof, gap-filling adhesive that bonds dissimilar materials (wood, metal, stone, concrete, foam) and is moisture-cured. Both are essential for carpentry, joinery, panelling and general construction bonding.
These adhesives follow IS / EN bonding standards. Major brands: Fevicol (Pidilite), Araldite (PU/epoxy), Jowat, Henkel (Loctite), Wurth, Bostik, Dr. Fixit.
PVA (Polyvinyl Acetate) Adhesive
PVA is a water-based, white / yellow emulsion adhesive that dries clear & bonds porous materials by absorption + evaporation. The most common is Fevicol — India's default wood adhesive. It is easy to use, non-toxic, low-odour, and economical.
PVA Types
| Type | Description | Use |
|---|
| Standard White PVA (D1/D2) | Interior wood glue | Furniture, joinery (dry) |
| Cross-Linked PVA (D3) | Water-resistant | Kitchens, humid areas |
| D4 PVA | Waterproof (exterior) | Exterior joinery |
| Yellow PVA (aliphatic) | Stronger, sandable | Fine woodwork |
| Synthetic Resin (SR) Adhesive | Heavy-duty wood bonding | Laminates, plywood |
PU (Polyurethane) Adhesive
PU adhesive cures by reacting with moisture (in air / substrate), foaming slightly to fill gaps, forming a very strong, waterproof, flexible bond. It bonds a wide range of materials — wood, metal, stone, concrete, ceramics, foam, plastics — making it highly versatile.
PU Types
| Type | Description | Use |
|---|
| One-Component PU (1K) | Moisture-cure, gap-filling | General bonding, dissimilar materials |
| Two-Component PU (2K) | Resin + hardener, fast / strong | Structural / industrial bonding |
| PU Construction Adhesive | Cartridge, high grab | Panels, skirting, fixtures (no nails) |
| PU Wood Adhesive (D4) | Waterproof wood glue | Exterior joinery, marine |
| PU Foam Adhesive | Expanding | Insulation boards, gaps |
PU vs PVA
| Parameter | PU Adhesive | PVA (Wood Glue) |
|---|
| Base | Polyurethane (moisture-cure) | Water-based emulsion |
| Water Resistance | Waterproof | D1–D2 not; D3–D4 yes |
| Bonds Dissimilar Materials | Yes (wide range) | Mainly porous / wood |
| Gap Filling | Yes (foams) | No |
| Strength | Very high | High (wood) |
| Flexibility | Flexible | Rigid |
| Cure | Moisture (foams) | Evaporation |
| Cost | Higher | Lower |
| Best For | Mixed materials, waterproof, gaps | Woodwork, laminates, furniture |
Where to Use
PVA
- Wood-to-wood joints (furniture, joinery)
- Veneer & laminate bonding
- Plywood / board lamination
- Paper, cardboard, crafts
- Wood primer / sealer (diluted)
- Interior carpentry (D1/D2); kitchens (D3); exterior (D4)
PU
- Bonding dissimilar materials (wood-metal-stone)
- Construction adhesive (panels, skirting, trims — no nails)
- Exterior / marine joinery (waterproof)
- Fixing insulation boards
- Stone / tile / concrete bonding
- Foam & gap-filling bonds
- Structural bonding (2K)
Other Common Construction Adhesives
| Adhesive | Use |
|---|
| Epoxy (2K) | Metal, stone, structural, high strength |
| Cyanoacrylate (Super Glue) | Instant small bonds |
| Contact Adhesive (Rubber) | Laminate / sunmica to board |
| Synthetic Rubber (SR) | Laminate, leather, rubber |
| Acrylic Adhesive | Plastics, signage |
| Hot Melt | Edge banding, packaging |
Top Brands
| Brand | Products |
|---|
| Fevicol (Pidilite) | Fevicol SH/SR, Marine, Heatx, Probond (PU) |
| Araldite (Pidilite) | Epoxy & PU adhesives |
| Henkel (Loctite) | PU & instant adhesives |
| Jowat | Industrial woodworking adhesives |
| Wurth | PU construction adhesives |
| Bostik | Adhesives & sealants |
| Dr. Fixit (Pidilite) | Construction adhesives |
Application
PVA
- Clean & dry both surfaces
- Apply even coat of PVA on one / both faces
- Join & clamp under pressure
- Wipe excess glue
- Clamp for 30 min–few hours; full cure 24 hr
PU
- Clean surfaces; lightly dampen one face (PU needs moisture)
- Apply PU adhesive on one face
- Join & clamp (PU foams & expands)
- Wipe excess (cured PU is hard to remove)
- Clamp during cure (foaming pushes apart)
- Full cure 24 hr; trim excess foam
PU needs moisture & clamping: PU cures by reacting with moisture — lightly dampen one surface. It foams as it cures, so always clamp firmly or the expanding foam will push the joint apart.
Advantages
PVA
- Easy to use, non-toxic, low odour
- Strong wood bond
- Dries clear
- Economical
- Water-clean-up (wet)
- Waterproof grades (D3/D4) available
- Long shelf life
PU
- Bonds dissimilar materials
- Waterproof & weatherproof
- Gap-filling (foams)
- Very high strength
- Flexible bond
- Construction adhesive (replaces nails)
- Wide temperature resistance
Disadvantages
PVA
- Not waterproof (D1/D2)
- Only porous / wood materials
- No gap-filling
- Creeps under sustained load
- Affected by humidity (low grades)
PU
- Higher cost
- Foams / expands (needs clamping)
- Messy; hard to remove when cured
- Stains skin (wear gloves)
- Limited shelf life (moisture-sensitive)
- Needs moisture to cure
Cost (Approximate, Indian Market, 2025-26)
| Item | Cost |
|---|
| PVA Wood Glue (per kg) | Rs 120 – 300 |
| Waterproof PVA D3/D4 (per kg) | Rs 250 – 500 |
| PU Adhesive (per 250–500 g) | Rs 200 – 600 |
| PU Construction Adhesive (cartridge) | Rs 250 – 600 |
| 2K PU / Epoxy Adhesive | Rs 300 – 1,000 |
| Contact Adhesive (per litre) | Rs 200 – 450 |
Best Practices
- Use PVA for interior woodwork; D3/D4 for kitchens / exterior
- Use PU for dissimilar materials, waterproof & gap-filling bonds
- Clean & dry surfaces before bonding
- Dampen one surface lightly for PU (moisture cure)
- Always clamp PU joints (foaming pushes apart)
- Apply even, adequate coat (not too much)
- Wipe excess before cure (esp. PU)
- Wear gloves with PU (stains skin)
- Allow full cure (24 hr) before load
- Store PU sealed (moisture-sensitive)
- Use contact adhesive for laminate / sunmica
- For tile / stone bonding, prefer tile adhesive
- For flexible weatherproof joints, use silicone sealant
Applicable Standards
| Standard | Description |
|---|
| IS 4835 | Polyvinyl Acetate Dispersion Adhesives for Wood |
| EN 204 / EN 14257 | Wood Adhesive Durability Classes (D1–D4) |
| IS 851 | Synthetic Resin Adhesives for Wood (Phenolic / Aminoplastic) |
| EN 15425 | One-Component Polyurethane Adhesives for Timber |
| ASTM D905 / D4317 | Adhesive Bond Strength / PVA |
| IS 9188 | Performance Requirements for Adhesives |
Conclusion
PVA and PU adhesives cover most bonding needs in construction & carpentry. PVA (white wood glue) is the economical, easy standard for interior woodwork — with waterproof D3/D4 grades for kitchens & exterior. PU adhesive is the stronger, waterproof, gap-filling, versatile choice for bonding dissimilar materials & construction fixing (replacing nails). Choose by material, water exposure and strength needs; always clean surfaces, clamp PU joints, and allow full cure.
For tile / stone bonding, use tile adhesive & epoxy grout; for flexible weatherproof / glazing joints, use silicone sealants; for mechanical fixing, nails, screws & anchor bolts.