Every contractor who has bought construction chemicals in India has at some point been confused by the GST rate. Is it 5%? 18%? Sometimes both on the same invoice? The confusion is understandable because the answer depends on the specific product and its classification under India's HSN coding system, not on who makes it or how it's sold.
This article gives you the practical answer for the products you actually buy.
The Short Answer
Most construction chemicals attract 18% GST. A specific, limited set of cement-based products attract 5% GST under Chapter 38 and Chapter 32 of the customs tariff schedule. There is no negotiation or interpretation here, the rate is determined by the HSN code of the product.
Which Products Attract 5% GST
Under GST notification, certain adhesive preparations and waterproofing products based on cement attract the lower 5% rate. In practical terms for construction chemicals buyers in India, the 5% rate typically applies to:
- Cementitious tile adhesives (C1, C2 grade polymer-modified mortars): HSN 3824 or 3214. Products like Sika Ceram, Fosroc Nitofix, BS Tileasy HS typically attract 5%.
- Cementitious grouts (tile joints, non-shrink structural grouts): also typically 5% under HSN 3824.
- Cement-based repair mortars: Products like Sika MonoTop, Fosroc Renderoc, BS Repail when classified as cement-based formulations under HSN 3824.
- Cementitious waterproofing coatings: Two-component cement-polymer systems (SikaTop 107, BS MoistureZero 2K) may attract 5% depending on classification.
Important caveat: The exact rate depends on the manufacturer's GST classification and the HSN code on the invoice, not on the product description. Different manufacturers sometimes classify similar products under different HSN codes, resulting in different rates. Always check the HSN code on your supplier's invoice and verify the applicable rate.
Which Products Attract 18% GST
The 18% rate applies to most synthetic polymer-based construction chemicals:
- Polyurethane sealants and membranes: Sikalastic 1K, Sikaflex, Fosroc Nitoseal, Tremco Dymonic, all 18%.
- Epoxy systems: All two-component epoxy adhesives, coatings, and injection resins, 18%.
- Acrylic coatings and waterproofing membranes, 18%.
- Concrete admixtures (superplasticisers, retarders, accelerators), 18%.
- Primers (epoxy, PU, acrylic), 18%.
- Crystalline waterproofing systems, 18%.
- Epoxy grouts, 18%.
- Crack injection resins (epoxy, PU), 18%.
Why This Matters for Input Tax Credit
If you're a GST-registered contractor or builder purchasing materials for a business project, you can claim Input Tax Credit (ITC) on the GST you pay on construction chemicals. This means the effective cost of the chemical is the ex-GST price, the GST component is recoverable.
If you're an end consumer (homeowner buying chemicals for your own property), there is no ITC, and the GST rate directly affects your cost.
The ITC chain requires that your supplier's GST returns are filed and that you have a proper GST-compliant invoice with GSTIN, HSN codes, and the applicable rate for each line item. A supplier with unfiled returns will break your ITC claim under GSTR-2B reconciliation.
GST on Freight and Delivery
Freight/logistics charges on construction chemical delivery attract 5% GST if billed separately on the invoice, or 18% GST if the freight is bundled into the product price (which is the more common case on online orders). This is a minor point but comes up in GST reconciliation.
Practical Verification: How to Check Your Invoice
- Locate the HSN code on each line item of your supplier invoice.
- Cross-reference HSN code against the GST rate schedule (available at cbic.gov.in).
- Confirm the GSTIN of your supplier is valid and active at gst.gov.in.
- Ensure the invoice shows your GSTIN (as buyer) if you're claiming ITC.
GST on B2B vs B2C Transactions
For B2B transactions (registered business buying from a registered supplier), the supplier collects GST and the buyer claims ITC. Net cost to the buyer is the pre-GST price.
For B2C transactions (individual or unregistered buyer), there is no ITC. The buyer bears the full GST cost. This is why the same product bought from Technotrade will show a GST component on the invoice, it's the statutory requirement, regardless of the amount.
Project Procurement: How Technotrade Handles GST
- All Technotrade invoices include HSN codes and applicable GST rates per line item.
- Our GSTIN is 08AAJPC2902J1ZY (Rajasthan, state code 08).
- For purchases from our online store (store.technotrade.in), you can enter your GSTIN at checkout to receive a B2B GST invoice.
- For project and bulk orders, GST-compliant proforma invoices are available on request.
- We file our GST returns on time, your ITC claims will reconcile correctly on GSTR-2B.
For questions about the GST treatment of a specific product you're procuring, WhatsApp our team at +91 97990 04515. For product technical questions, WhatsApp Divya at +91 92568 16832.
Note: GST rates and classifications are subject to revision by the GST Council. This article reflects the rate structure as of 2025. Verify current rates for specific HSN codes at cbic.gov.in before finalising project budgets.
Technotrade Associates, Jaipur, GSTIN: 08AAJPC2902J1ZY. GST-compliant invoicing on all orders, ITC-safe supply chain for B2B buyers.
