A congregation's property was built in pieces, decades apart, by whoever sat on the trustees at the time — and twice a week it has to move a few hundred people across wet pavement in dress shoes. This page is written for the volunteer facilities committee: how to read the whole campus, which repairs you can order off the shelf and install on a work day, and where to stop shopping and get the parking lot quoted.
A campus assembled in pieces, drained by nobody in particular
Almost no house of worship was master-planned. The sanctuary went up first, the fellowship hall arrived when the congregation outgrew the basement, the education wing came with the baby boom, and the lot was paved outward in three or four campaigns as the road frontage allowed. Each addition brought its own roof, its own downspouts and its own pavement, drained by whatever the contractor of that decade thought reasonable. Nobody has ever stood on the property with a plan of the whole thing, because there has never been one.
That history produces a recognizable set of problems. Roof area is enormous relative to site area, because a sanctuary is one very large room under one very large roof, and its leaders dump concentrated flow onto walks poured flat. Pavement joints between building campaigns run downhill in directions nobody intended. And the campus is empty five days out of seven, so the storm that does the damage happens with nobody there to see where the water went; what the committee sees on Sunday is the aftermath.
Then there is the traffic pattern, unlike almost any property we sell into. Four hundred people arrive inside a twenty-minute window and leave inside a ten-minute one, on foot, in weather, and a real share of them are elderly, using a cane, holding an umbrella, or carrying a toddler. A grate that is perfectly acceptable in a warehouse yard is a genuine trip hazard on a church walk at 12:05 on a rainy Sunday — grate selection here is a safety decision before it is a hydraulic one. And unlike most sites, the cheap answer, move dirt, is often off the table: you do not regrade a memorial garden with interments in it, or drop the grade at a cornerstone.
What the property needs, zone by zone — including the parts we do not sell
Walk the campus once as a whole rather than chasing complaints, and it resolves into six zones plus one honest boundary.
The sanctuary roofline — the largest number on the site
An 8,000 sq ft sanctuary roof sheds about 4,980 gallons per inch of rain, and never evenly: the two leaders at a cross-gable valley can carry triple what the corner leaders carry. The fix is not a bigger downspout, it is catching what the downspout delivers at grade and piping it away in solid pipe — an adapter into a catch basin, or a short channel run across the walk below the leader. Detail on our downspout drainage page.
The accessible entry, the drop-off and the covered porch
This is where a drainage defect becomes an access problem. An accessible route is held to a maximum cross slope of 1:48 and a running slope of 1:20 before it counts as a ramp, so accessible walks and landings are nearly flat by design — which means they pond by design. Water leaves here by being collected, not by tipping the slab: a channel across the approach or at the base of the ramp, tied to pipe, with a grate chosen against the rules in ADA and pedestrian drainage.
The parking lot, the fire lane and the coach approach
The lot is the biggest impervious area on most campuses and the one place we tell congregations to stop shopping and start a quote. Lot work means saw-cutting, load class, an outlet with somewhere legal to go and usually a permit, and the products that belong in it are engineered systems configured per project. Send it as a request for quote and we price it against run length and load class rather than guessing.
The courtyard, the breezeway and the memorial garden
Additions create enclosed spaces — a court between sanctuary and education wing, a covered breezeway to the preschool door, a memorial patio with a bench — and these often have no downhill side at all, so a perimeter line and a sump are the only exit water has (our courtyard drainage page covers the no-exit case). The memorial garden and columbarium are the same problem with a higher standard of finish: a narrow channel at the edge of the paving rather than through it, a basin tucked into a bed with a domed grate that stands above the mulch, and decorative iron on anything that shows. Nobody should be putting a bare galvanized bar grate in a garden of remembrance.
The fellowship hall's exterior side
The outside of a fellowship hall works harder than its size suggests: a service door where the food pantry receives pallets, a rear apron for the mission trailer, a dumpster pad, a folding-table door onto a slab an inch too low. Everything we spec here is exterior surface drainage. To be plain about the boundary: interior kitchen drainage under a health code is a different product class entirely — hygienic and GMP-style systems mean engineered sanitary stainless with crevice-free welds, and we do not sell those. A kitchen renovation with interior floor drains under an inspector's eye is a plumbing and sanitary-stainless supplier's scope. We handle general-duty and exterior zones.
Subsurface systems, and the rest of what is not ours
Plenty of church property has a genuine subsurface problem: a churchyard that will not dry between services, a burial ground on clay, a youth ballfield unplayable for three days after a storm. The right answer there is often a french drain or a field underdrain — perforated pipe bedded in washed stone, wrapped in filter fabric, trenched below grade to pull water out of saturated soil. That is a different physical job from catching water off a surface, it is contractor-installed, and we do not sell it. What we sell is the surface layer that feeds it and outlives it: basins at the low points, channels across the paving, grated inlets in turf, solid pipe fittings, and the discharge end. Never let a supplier call a channel drain or a catch basin a french drain — they do opposite jobs.
Sanitary sewer, septic and building plumbing. This page is surface stormwater only; your sanitary system is a separate trade and a separate conversation.
Pumps, sump systems and interior waterproofing. An undercroft that takes water needs a waterproofing contractor. We sell no pumps and no interior systems.
Separators, interceptors, detention and treatment. Oil and water separators, grease interceptors and any treatment device are downstream of us, by others. We stop where the pipe leaves the collection point.
How water moves across a campus, and how to check the system has room
Fifteen minutes of arithmetic prevents the two most common church drainage failures: a handsome new drain that is too small, and a handsome new drain emptying into a pipe that was already full.
The puddle is the symptom; the concentration point is the cause. Water gathers in four predictable places here — under roof leaders and scuppers, at the crease where two building campaigns meet, at the bottom of the lot where the last paving contractor stopped, and along any curb line running toward a door. Stand outside during one real rain; it teaches more than a season of complaints. Then find the low point, because every surface has one, and the art of surface drainage is putting a collection point there and getting the water out in pipe before it spreads.
Now the arithmetic. Every 1,000 sq ft of hard surface produces about 623 gallons per inch of rain. An 8,000 sq ft sanctuary, a 6,000 sq ft fellowship hall and a 5,000 sq ft education wing total 19,000 sq ft, or roughly 11,800 gallons in a 1 in. storm, before any parking is counted. Volume tells you the scale; rate tells you what to buy. The rational method is Q = C × i × A, with A in acres, i in inches per hour, and C the fraction that runs off — about 0.95 for roofs, asphalt and concrete, roughly 0.20 to 0.35 for turf. As a benchmark, 1 in. per hour on one acre is about 1 cubic foot per second, or 449 gallons per minute. A 60-space lot with aisles is around 19,500 sq ft, or 0.45 acre; in a 3 in. per hour storm it produces about 1.28 cfs — 575 gpm — arriving all at once at whatever sits at the low end. Run your own numbers in our Runoff Calculator and read the method in Sizing for Storms: Estimating Runoff.
Then check the outlet, because the channel almost never limits the system — the pipe does. A drain that "clogs" every storm is usually discharging into an undersized, silted or crushed line somebody buried in 1978.
What an outlet pipe carries — smooth wall, running full, 1% slope
Outlet size
Approximate capacity
What that realistically covers
4 in.
~110 gpm (0.25 cfs)
One or two downspout leaders; a short channel beside a walk
6 in.
~330 gpm (0.73 cfs)
A fellowship hall roof plane; a courtyard; one door-threshold run
8 in.
~700 gpm (1.6 cfs)
A sanctuary roof plus its plaza; one bay of parking
Manning's equation, n = 0.010 smooth-wall, flowing full at 1% slope; corrugated pipe carries materially less, and nothing runs full and clean for long, so design to 75–80% of these figures. Cross-check at the inlet too: a 12 in. cast iron catch basin grate (NDS 1213) passes 113.80 gpm at 1/2 in. of head, so one basin top is roughly one 4 in. pipe's worth of water. Set that against the 575 gpm of the example lot and the answer writes itself — that lot needs an 8 in. line or more than one collection point. Grate flow rates and class definitions are in our Load Class Recommendation Guide.
Load class, from the prayer garden path to the trash truck
You will use three or four ratings on the same property. Under EN 1433 the classes are named by test load in kilonewtons:
Class A 15 — pedestrian only: garden paths, the columbarium walk, a plaza no vehicle enters. Never where the mower deck, a lift for the Christmas banner, or the caterer's van crosses.
Class B 125 — cars and light vehicles at low speed: walks a maintenance pickup crosses, the porch where the shuttle van pulls up.
Class C 250 — the working default for a lot: stalls, curb lines, drive aisles, the drop-off. Also the right floor for a garden path if a truck ever crosses it for a burial or a tree removal.
Class D 400 — a 400 kN test load, for the fire lane, the trash truck approach, the coach turn on a campus running a bus ministry, and the dumpster pad. Committees under-spec this constantly, because the trash truck is not there on Sunday when they walk the site.
Class E 600 and F 900 — industrial docks, ports, airfields. A house of worship essentially never needs them.
American drawings usually speak AASHTO instead. Our trade heuristic is that H-20 corresponds to a 16,000 lb wheel load and HS-25 to 20,000 lb, landing broadly in Class C to D territory — a shop rule for picking a grate off a shelf, not a formal equivalence between standards, and on a permitted lot the engineer of record sets the number.
Two rules matter more than the label on the box. The pour rates the drain, not the part: published classes assume full concrete encasement per the manufacturer's instructions. And set the grate 1/8 in. to 1/4 in. below the finished surface so wheels load the encasement, not the grate edge. Near a door, one more governs everything: openings must not pass a sphere larger than 1/2 in., and elongated slots must run perpendicular to the direction of travel. A Spee-D slot is 3/8 in. by 3-1/4 in., so it passes on size — but a run laid the wrong way still catches a cane tip, and orientation is free at install and expensive afterward.
Where each kind of drain earns its keep on this property
Replacement grates — the job congregations actually order
The most common church order we ship is not a system, it is a stack of grates. Twenty years of UV, road salt, a snow shovel and one dropped scaffold leg leave a walk with three cracked grates, one missing and two replaced in a color nobody matched. Re-grating needs no concrete work, is genuinely a work-day job for two volunteers with a screwdriver, and fixes the trip hazard that put it on the agenda. The full material range — cast iron, ductile iron, steel, brass — lives in the grates section with dimensions on every page.
Basins in the beds, channels at the thresholds
Church grounds get mulched every spring by people who love the property, and after fifteen springs the grade has risen two or three inches — the basin is not clogged, it is below the ground it is meant to drain. Catch basins come in 9 in., 12 in., 18 in. and 24 in. square plus round, and every size has a matching riser. A channel, by contrast, earns its place only where water crosses as a wide sheet: a door threshold, the base of a ramp, the low edge of a court. The mistake we see most here is a long, expensive run laid parallel to the flow instead of across it, intercepting almost nothing.
The discharge end — where church systems are usually incomplete
Half the systems we are asked to diagnose end in a pipe that goes eighteen feet and stops. Give the water a release: a pop-up emitter that opens under pressure and closes flush so the mower rides over it, or a dry well where there is nowhere to daylight. Everything between is drainage fittings, and getting that list right the first time keeps one work day from becoming two.
Finishes for the places people look at, locks for the days nobody is here
In a memorial garden or at a formal entrance the grate is a finish material. Atrium grates are domed, so they stand proud of mulch and keep drawing where a flat grate would vanish under bark chips; decorative grates cover Botanical and Wave in plastic and cast iron, and the Dura-Slope iron line adds weave, diamond and tile patterns. And because an unattended campus is a soft target where loose metal walks, every serious line sells a hold-down — Filcoten anti-vandalism locking devices for the 100, 200 and 300 systems, the NDS Dura-Slope ProFit grate lock, Micro Channel hold-down clips, ACO QuickLok removable bars — alongside silt and trash buckets that catch the autumn leaf load where a volunteer can lift it out by hand.
What we would put on a congregation's order, and why
Before spending anything on new systems, re-grate what you already own. A standard Spee-D grate is 24 in. × 4-1/8 in. × 3/4 in., with 3/8 in. × 3-1/4 in. slots giving 16.92 sq in. of open area per foot at Class B 125 — in six colors, so a 1990s walkway comes back to one finish. The Mini and Pro Series families do the same for those channels. We lead with this because it removes the hazard the committee is actually worried about, needs no concrete, and costs a fraction of any alternative.
Planted beds · turf low points · memorial garden edges
Order the riser sized to the basin (9 in., 12 in., 18 in., or a 24 in. extension) together with the grate that caps it, and reset the assembly flush with today's grade rather than 1998's — a 12 in. riser is 12-3/8 in. square by 7-1/8 in. tall, usually one more than people expect. Cap it with an atrium grate in a bed or a cast iron grate where wheels cross. Capacity check: the 12 in. cast iron top passes 113.80 gpm at 1/2 in. of head, so one basin handles a downspout pair in a heavy storm, not a whole roof.
The door that floods every storm, fixed on a Saturday — NDS Spee-D Channel
Fellowship hall doors · side entries · preschool walks · volunteer install
Spee-D is the line we point volunteer crews at more than any other: 4 ft and 10 ft sections, grates in six colors, and a footprint small enough to trench by hand. Run it across the water at the threshold, tie it to 3 in. or 4 in. solid pipe, and give it somewhere to go. Longer runs or heavier flow step up to 5 in. Pro Series, which carries pedestrian plastic through galvanized steel and ductile iron on the same channel. Background: Spee-D FAQs and 5 in. Pro Series resources.
The accessible entrance, where the grate is a legal surface — BG Filcoten TEC V100
ADA routes · ramp bases · main entry plazas · heel-proof
Where the drain sits in the accessible route we spec a 4 in. fiber-reinforced HPC channel and a grate the manufacturer states is heel-proof and ADA: the Filcoten 100 ductile iron bar grate in Class C 250 or Class D 400, or the composite honeycomb in Class C. Bodies come both without slope and with a built-in 0.5% fall, which matters enormously at an entrance you cannot re-pitch; add the silt bucket if there are trees. For a heavier or more architectural entry, Josam Pro-Plus 100 carries ADA/heel-proof galvanized, stainless and ductile iron grates from Class A through Class F — a line we quote on request. See the Filcoten FAQs.
The sanctuary leader that dumps on the walk — 12 in. basin into solid pipe
Land the downspout in a basin, pipe it away, and stop the splash-back quietly working on the masonry and window sills. Sizing anchor: an 8,000 sq ft sanctuary roof yields roughly 4,980 gallons per inch of rain, unevenly split among its leaders. Where two land close together or a valley concentrates, go to an 18 in. basin and a 6 in. outlet rather than doubling up on 4 in. lines. Where the leader lands mid-walk with no room for a basin, a 5 in. Pro Series run across the walk does the same work.
Two moves. In the beds, a basin with an atrium grate standing above the mulch line, still drawing after volunteers top-dress in April. On the paving, a narrow Mini Channel — 6 ft sections, 3.5 in. wide, grates in plastic, brass and iron — set at the edge of the stone rather than through the middle of it. For the visible pieces, Botanical and Wave come in cast iron as well as color-matched plastic. This is the one zone where we say spend on the grate and save on the channel: nobody will ever see the channel again.
The drop-off lane and the porte-cochere — NDS Dura-Slope
Covered entries · van and shuttle lanes · long flat runs · Class C
The covered drop-off is dead flat, wide, and the busiest twelve feet on the property. Dura-Slope carries a built-in slope so a long run keeps water moving without the pavement doing the work, and the in-line catch basin (DS-340) holds the system's 0.7% fall through the collection point instead of killing it. Add the trash bucket (DS-240) under mature trees and the ProFit grate lock (DS-122) on an unattended campus. Grates run from pedestrian plastic through cast iron and the decorative patterns, so one system serves the traffic lane and still looks right at the front door. Full matrix in the Dura-Slope FAQs.
The parking lot, the fire lane and the bus turn Quote only
ACO PowerDrain · KlassikDrain · MiniKlassik · RFQ, never cart
Once the work moves into the lot it moves into engineered systems configured per project. ACO PowerDrain (S100K, S200K, S300K) is the ductile-iron-edge line for drive lanes and fire lanes; ACO KlassikDrain (K100/KS100 through K300/KS300) covers entrances, plazas and heavier civil work, with in-line catch basins, QuickLok locking bars and trash buckets in the same family; MiniKlassik K50 handles narrow architectural runs. All ACO lines are quote-only and never sold from the cart — send run length, load class and depth to request a quote and we come back within one business day.
Flat sites · tight urban lots · the end of every run
Many congregations sit on flat ground with a property line where the grade ought to be. A pop-up emitter releases at grade in turf and closes flush so the mower rides over it, in 3 in., 4 in. and 6 in. sizes. Where there is no lower ground at all, a Flo-Well unit holds roughly 50 gallons and stacks or chains in series, so you size the field by dividing the volume you need to hold by 50 — a 4,000 sq ft roof plane sheds about 2,490 gallons in a 1 in. storm, which is a sobering number of units and exactly the check worth running before the trencher shows up.
Buying it the way a congregation actually buys
Send a zone list, not a wish list. Sanctuary roofline, accessible entry and drop-off, courtyard, fellowship hall exterior, memorial garden, parking lot, turf low points. For each: what is there now, the count, the color, and the load class if anything with wheels crosses it. Photographs of one grate per type, with the number molded into the underside legible, beat any written description. We come back within one business day, itemized by zone.
Ask for it split by zone. A committee handed one lump sum defers the whole thing; a committee handed seven line items approves five and schedules two. Splitting also protects the entry — when the total runs past what the trustees will carry, the temptation is to quietly substitute a cheaper grate at the accessible door, and that is the one place on the property where the cheap grate becomes a claim.
Know what ships and what gets quoted, then work backward from the work day. Stocked NDS, Filcoten and Stegmeier items ship as ordered; the ACO lines are quote-only and configured per project, and the Josam lines we quote on request, so anything involving the lot or an engineered entry starts weeks ahead rather than the week of. Volunteer labor arrives on one Saturday and does not come back — order every fitting, coupling, end cap and outlet in one shipment with a spare of each, and give us the maintenance building or service door plus a mobile number, not a church office that closes at 1 p.m. Thursday.
What facilities committees ask us
Our grates are cracked and mismatched. Can we replace just the grates?
Almost always, and it is the cheapest fix on the property. Pull one and measure it. An NDS Spee-D channel grate is 24 in. long, 4-1/8 in. wide and 3/4 in. thick, with 3/8 in. by 3-1/4 in. slots giving 16.92 sq in. of open area per foot at Class B 125. It comes in White (240), Gray (241), Green (242), Black (243), Sand (244) and Brick Red (251), so a twenty-year-old walkway can be re-grated in its original color. Photograph the number molded into the underside, count the pieces, and send us both.
Which grates are safe to put on an accessible entrance route?
The ADA Standards section 302.3 rule is that openings in a walking surface must not pass a sphere larger than 1/2 in., and elongated openings must be set with the long dimension perpendicular to the direction of travel. A standard NDS Spee-D slot is 3/8 in. wide, so it passes on opening size, but you still have to lay the run so the slots cross the path rather than run along it. Where the entrance is formal, we step up to a grate the manufacturer states is heel-proof and ADA: the Filcoten 100 ductile iron bar grate in Class C 250 or Class D 400, or the Filcoten 100 composite honeycomb in Class C.
What load class does the church parking lot and fire lane need?
Class C 250 under EN 1433 covers parking stalls and car drive aisles. Go to Class D 400, a 400 kN test load, anywhere the trash truck, the fire lane, a coach bus or a food truck crosses the grate, which on most campuses is the same strip of pavement. American drawings often speak AASHTO instead, where H-20 is a 16,000 lb wheel load and HS-25 is 20,000 lb. Treat that crossover as a shop heuristic for picking a grate, not as a formal standards equivalence, and let the engineer of record set the number on a permitted lot.
How much water does a sanctuary roof actually shed?
Every 1,000 sq ft of roof produces about 623 gallons per inch of rain. An 8,000 sq ft sanctuary, a 6,000 sq ft fellowship hall and a 5,000 sq ft education wing come to 19,000 sq ft, roughly 11,800 gallons in a 1 in. storm, before a square foot of parking is counted. Rate matters more than total volume when you size: 1 in. per hour on one acre is about 1 cubic foot per second, roughly 449 gallons per minute.
Our catch basins have sunk or vanished under mulch. What do we order?
A riser and a grate, ordered as a pair. NDS makes a 9 in. riser (916), a 12 in. riser (1216) at 12-3/8 in. square by 7-1/8 in. tall, a riser for the 18 in. basin (1816), a 24 in. extension (2418) and a Spee-D basin riser (101R). Reset the grate flush with the grade the volunteers actually maintain, then write mulch clearance into the grounds crew's list. Most church basins we get asked about are not clogged, they are buried.
Do you sell french drains for the lawn, the ballfield or the cemetery?
No. A french drain is perforated pipe bedded in washed stone and wrapped in filter fabric, trenched below grade to pull water out of saturated soil. It is real drainage and plenty of church property needs it, but it is contractor-installed subsurface work we do not sell. What we sell is the surface collection layer that feeds it and outlives it: catch basins, channel and trench drains, grated inlets, solid pipe fittings, pop-up emitters and dry wells.
Send the zone list, counts, grate colors and load classes — we will match what is already in the ground, spec the new runs, and get an itemized quote back to you within one business day.
