Interior Basement Drain System Break-Even: $80K Monthly Revenue

Fixed costs $10.9K/mo Monthly base cost

Contribution margin 70% After variable costs

Break-even revenue $15.5K/mo Monthly target

Break-even timing Month 3 Launch ramp

Break-even calculator

Use this calculator to test whether monthly revenue can cover variable expenses and fixed costs for an interior basement drain system contractor.

Lean Base Full

Monthly revenue Revenue drives the margin left after direct job costs. $ Slow month Strong month Variable expenses These are the direct costs that rise with each project. $ Lower cost Higher cost

Money available to cover fixed costs $607,540 $821,000 revenue - $213,460 variable expenses

Margin ratio

74%

Covers fixed costs

Yes

Fixed monthly costs This is the monthly payroll and overhead base the margin has to cover. $ Lean setup Heavier setup

Break-even chart Revenue Total costs

Which expenses are fixed, and which move with sales for an interior basement drain system installer?

Cost classification

Break-even works only if each expense follows the right driver. Here’s the quick math: Year 1 revenue is $4.272 million, so every 1% misclassified as fixed or variable shifts annual break-even logic by about $42,720.

Expense	Cost	Break-Even Treatment	Common Mistake
Raw materials and hardware	Variable	Use 18% of Year 1 revenue in the contribution margin.	Treating drain tile, gravel, pipe, and hardware as fixed because vendors are reused.
Direct project disposal fees	Variable	Use 4% of Year 1 revenue tied to completed jobs.	Leaving concrete and debris disposal below the break-even line.
Vehicle fuel and maintenance	Variable	Use 5% of Year 1 revenue because truck use rises with job volume.	Budgeting fuel like rent instead of linking it to route load and installs.
Sales commissions	Variable	Use 3% of revenue as a direct selling expense.	Counting commission inside fixed payroll and overstating contribution margin.
Installation crew labor	Semi-variable	Model base field payroll as capacity, then add overtime or crews as jobs increase.	Treating salaried field capacity as free once hired.
Warehouse and office rent	Fixed	Use $4,500 monthly through the relevant planning range.	Spreading rent across jobs and making break-even look better at low volume.
Utilities and internet	Semi-variable	Use the $800 monthly baseline, with usage rising as crews and warehouse hours grow.	Assuming the full bill moves directly with each installation.
Marketing budget	Semi-fixed	Use $45,000 in the first year and step it up as lead targets grow.	Treating all marketing as a per-job variable expense instead of a planned capacity spend.

How does break-even change from a lean ramp to a base crew and a full Year 1 run-rate for an interior basement drain system?

Scenario table

Break-even shifts mainly because fixed overhead is $55,900 a month while variable costs hold at 30% of revenue. At $64,000 in sales the model is short, at $80,000 it is basically flat, and at the Year 1 run-rate it has a wide cushion.

Planning case figures use the model's assumptions and show direction, not a promise of results.

Scenario	Monthly Revenue	Variable Costs	Fixed Costs	CM Ratio	Operating Profit	Break-Even Signal
Lean owner-led ramp	$64,000	$19,200	$55,900	70%	-$11,100	Still below break-even and short on overhead coverage.
Base one-crew break-even	$80,000	$24,000	$55,900	70%	$100	Essentially at break-even, with almost no cushion.
Full staffed Year 1 run-rate	$356,000	$106,800	$55,900	70%	$193,300	This run-rate leaves a strong cushion over fixed overhead.

What breaks the break-even plan for an interior basement drain system?

Stress test

The plan breaks even at about $79,900 a month, but it gets tight if leads slow or job costs creep up. The main risks are fewer qualified leads, fuel and disposal overruns, callbacks, and slower collections.

Stress Case	Changed Assumption	Break-Even Revenue	Revenue Gap	Risk Signal
Current plan	No change; variable expenses stay at 30%.	$79,900	$0 gap	Any slip in jobs or collections can turn the month red.
Revenue shortfall	Monthly sales fall to 8 jobs instead of 10.	$79,900	$11,100 gap	Fewer qualified leads can erase the cushion fast.
Fixed-cost increase	Fixed overhead rises 10% to about $61,500 a month.	$87,900	$7,900 gap	Higher overhead pushes break-even up even without more sales.
Margin pressure	Variable expenses rise to 35%, cutting contribution margin to 65%.	$86,100	$6,200 gap	Fuel, disposal, and callbacks cut margin quickly.
Combined pressure	Variable expenses rise to 35% and fixed costs rise 10%.	$94,700	$14,800 gap	Slow leads and cost overruns together create the hardest month.

What should you verify before you lease space, buy vans, and hire crews for an interior basement drain system?

Founder checklist

Don’t lock the lease, vans, or hiring until demand, margin, and cash line up with Month 3 break-even. The hard checks are a 10-install monthly pipeline, $450 CAC, $10,850 of fixed burn, and $701,000 of cash through Month 2.

1Install pipeline10+/mo, $450 CAC

Verify you can source at least 10 installs a month at a $450 CAC and an $8,000 ticket, because weak lead quality kills break-even before the first crew scales.

2Fixed burn$10.85K/mo

Keep fixed overhead near $10,850 a month and lock insurance before field work, because rent, systems, and coverage hit every month even when storm demand slows.

3Unit margin70% CM

Check that materials, disposal, fuel, and commissions still leave about 70% contribution margin, or the Month 3 break-even math stops working.

4Supply terms18% + 4%

Secure drain-material and hardware pricing around the Year 1 18% assumption and hold disposal near 4%, because high-volume jobs are where margin leaks show up first.

5Crew hours32 hrs/install

Train crews to finish each interior drainage install in 32 billable hours, so the staffing ramp stays aligned with capacity and rework does not eat paid time.

6Cash runway$174.5K + $701K

Fund the $174,500 startup capex and still keep $701,000 available through Month 2, with room for callbacks and slower collections.