Construction bookkeeping is rarely straightforward.
Between subcontractors, CIS deductions, VAT reverse charge, supplier bills, materials, project costs and monthly returns, it is easy for the books to drift if the process is not properly controlled.
Two areas cause particular confusion for construction businesses: CIS and domestic reverse charge VAT.
They are connected because both often apply to construction work, but they are not the same thing. CIS deals with subcontractor tax deductions. Domestic reverse charge VAT changes who accounts for VAT on certain construction services.
This guide explains the difference in plain English, why the bookkeeping matters, and what construction businesses should watch out for.
What is CIS?
CIS stands for the Construction Industry Scheme.
Under CIS, contractors may need to deduct money from payments made to subcontractors and pass those deductions to HMRC. Those deductions count as advance payments towards the subcontractor’s tax and National Insurance.
In practical terms, this means a contractor needs a clear process for:
- ✓Verifying subcontractors
- ✓Checking deduction rates
- ✓Recording labour and materials correctly
- ✓Preparing monthly CIS returns
- ✓Issuing subcontractor deduction statements
- ✓Keeping CIS suffered records where relevant
- ✓Reconciling CIS deductions back to the bookkeeping
Where this goes wrong, the accounts can quickly become unreliable.
The problem is not just compliance. If subcontractor costs are posted incorrectly, project profitability, VAT returns, management reports and year-end accounts can all be affected.
What is domestic reverse charge VAT?
Domestic reverse charge VAT is a VAT rule that applies to many supplies of building and construction services.
HMRC says the VAT domestic reverse charge must be used for most supplies of building and construction services where the supply is standard or reduced rate, the businesses are VAT registered in the UK, and the services are reported within CIS.
Normally, a supplier charges VAT on an invoice and pays that VAT to HMRC.
With domestic reverse charge VAT, the supplier does not charge VAT in the usual way. Instead, the customer accounts for the VAT on their own VAT return. HMRC’s technical guidance explains that where the construction reverse charge applies, the supplier does not charge VAT, and the liability to account for VAT shifts to the customer.
That is why it causes confusion.
The invoice may not look like a normal VAT invoice. The VAT return entries may be different. The accounting software needs to be coded correctly. Supplier bills need to be reviewed carefully before the VAT return is submitted.
CIS and reverse charge VAT are different
A common mistake is treating CIS and domestic reverse charge VAT as if they are the same thing.
They are not.
CIS is about tax deductions from subcontractor payments.
Domestic reverse charge VAT is about who accounts for VAT on certain construction services.
The two can overlap because domestic reverse charge VAT applies to certain services that are also reported within CIS. But each area still needs to be reviewed separately.
For example, a subcontractor invoice may need checking for:
- ✓Labour
- ✓Materials
- ✓CIS deduction treatment
- ✓VAT reverse charge wording
- ✓Whether VAT has been charged correctly
- ✓Whether the customer is an end user
- ✓Correct coding in Xero, QuickBooks, Sage or FreeAgent
This is why construction bookkeeping needs more than basic transaction posting.
Why construction invoices need careful review
For construction businesses, supplier bills and subcontractor invoices are often where the problems start.
Issues can include:
- ✓VAT charged when reverse charge should apply
- ✓Reverse charge applied when normal VAT treatment is needed
- ✓Materials not separated clearly
- ✓CIS deductions calculated on the wrong amount
- ✓Subcontractor verification not checked
- ✓Invoices posted to the wrong project
- ✓Supplier statements not reconciled
- ✓Retentions and applications for payment sitting outside the accounts
HMRC’s compliance guidance says that if a supplier charges VAT on supplies that should be reverse charged, the customer should reject the invoice and ask for a credit note or re-invoicing.
That is why checking invoices before posting and paying them matters.
If the bookkeeping team only processes what they are given without reviewing the treatment, errors can build up quietly until the VAT return, CIS return or year-end accounts are reviewed.
Common CIS bookkeeping problems
CIS errors usually come from weak process, not one-off mistakes. Common issues include:
Subcontractors not verified before payment
The correct deduction rate depends on the subcontractor’s CIS status. If this is not checked, deductions can be wrong.
Materials not separated properly
CIS deductions should generally apply to the labour element, not the direct cost of materials. HMRC’s CIS manual says deductions under the scheme should only be applied to the part of the payment that does not represent the direct cost of materials to the subcontractor.
CIS suffered not tracked properly
Subcontractor companies that suffer CIS deductions need those deductions tracked clearly so they can be claimed correctly through the company’s payroll scheme where relevant.
Monthly statements not issued clearly
Contractors need to provide subcontractors with deduction statements where deductions are made. HMRC guidance says the statement must be given within 14 days of the end of each tax month.
CIS records do not match the books
If the CIS return, supplier ledger and bank payments do not agree, it becomes difficult to know which figures are correct.
Common reverse charge VAT bookkeeping problems
Domestic reverse charge VAT problems usually appear in supplier bills, sales invoices and VAT return checks. Typical issues include:
The wrong VAT code is used
If software codes are not set up correctly, the VAT return may not reflect the reverse charge correctly.
Supplier invoices are posted without review
A bill may show VAT, reverse charge wording, zero-rated treatment or mixed supplies. Each needs checking before the VAT return is prepared.
End user status is not considered
Domestic reverse charge does not apply in every case. End user and intermediary supplier rules can change the treatment, so the invoice and customer status need to be reviewed carefully.
Standard, reduced and zero-rated work gets mixed up
HMRC guidance confirms the domestic reverse charge applies to standard and reduced rate services, but zero-rated supplies are treated differently.
VAT returns are prepared from unreviewed records
If the bookkeeping is messy, the VAT return may be technically filed on time but still based on unreliable records.
Why project costing matters too
CIS and VAT are compliance issues, but construction businesses also need useful management information.
A business owner needs to know:
- ✓Which projects are profitable
- ✓Which jobs are over budget
- ✓How much has been spent on subcontractors
- ✓Whether materials are being tracked properly
- ✓What is owed to suppliers
- ✓What is due from customers
- ✓Whether retentions and applications are being monitored
- ✓Whether cash flow is likely to tighten
If all costs are posted generally to the profit and loss account, the business may have no clear view of job-level performance.
Good construction bookkeeping should therefore connect compliance with reporting. CIS, VAT, supplier bills and payroll need to be posted in a way that supports both accurate filings and useful project reporting.
What a good construction bookkeeping process should include
A reliable construction bookkeeping process should normally include:
Subcontractor verification process
New subcontractors should be verified before payment, with deduction rates recorded clearly.
Supplier bill review
Invoices should be checked for VAT treatment, CIS relevance, materials, retentions and project coding.
Clear CIS records
Monthly CIS returns, deduction statements, CIS suffered records and subcontractor ledgers should be kept aligned.
VAT reverse charge review
Domestic reverse charge invoices should be reviewed before VAT returns are prepared.
Project or job tracking
Xero tracking categories, QuickBooks classes or another reporting structure should be used where job-level reporting is needed.
Regular reconciliation
Bank, supplier statements, subcontractor payments, VAT control accounts and CIS balances should be reconciled regularly.
Monthly reporting
Reports should show more than profit and loss. A useful pack may include cash flow, debtors, creditors, project costs and plain-English commentary.
When should a construction business get help?
You may need help reviewing your construction bookkeeping if:
- ✓CIS returns are being prepared from memory or spreadsheets
- ✓Supplier bills are piling up
- ✓VAT reverse charge treatment is inconsistent
- ✓You cannot see project-level profit
- ✓Retentions and applications for payment sit outside the accounts
- ✓Subcontractor statements are not clear
- ✓VAT returns feel rushed
- ✓Your accountant raises the same bookkeeping issues each year
- ✓You are relying too heavily on one person to keep everything moving
A clean-up can help, but the better long-term solution is a stronger monthly process.
How Better Bookkeeping Solutions supports construction businesses
Better Bookkeeping Solutions supports construction businesses with cloud bookkeeping, CIS, VAT review, payroll, supplier bills, project costing, management reporting and accounting software support.
We work across Xero, QuickBooks, Sage and FreeAgent, with connected apps where useful.
For construction clients, we help bring the moving parts together:
- ✓CIS verification and monthly returns
- ✓Domestic reverse charge VAT checks
- ✓Subcontractor records
- ✓Supplier bills and receipts
- ✓Payroll and labour costs
- ✓Project and job costing
- ✓Retentions, WIP and applications for payment
- ✓Management reporting and cash flow
The aim is simple: clearer records, fewer last-minute problems and financial information that is easier to rely on.
Need help with CIS, VAT reverse charge or construction bookkeeping?
Request a discovery call to review your current bookkeeping setup, CIS process, VAT reverse charge treatment and project reporting. We will help identify what is working, what needs improving and the most practical next step for your construction business.
