Singapore Trench Drain: Not Your Average Bar Grating

Hinged drainage grating is cool!!! I think we need to use more of it in the United States. A few US companies offer hinged cast iron grates, but, I’ve never seen hinged bar grating used in the United States.

hinged bar grate, bar grating, trench drain bar grates, specialty grating

The ability to open a drain for cleaning (which this drain needs) is essential. If drain grates are locked into place with a locking mechanism or if the grates are the bolt-down style, opening the drain becomes more problematic. But when the drain grates aren’t attached in some way, unscrupulous or financially desperate people could take the grates and trade them at the scrap yard. Hinged grating solves both of these problems. Grating can be removed for easy cleaning access while the still being attached.

Below is another hinged grating which uses the wide section of the bar stock as the walking surface. By placing the bars in this manner and minimizing the open space between them (1/4” or so), the designers of this grating have made a heel-proof and vandal proof trench cover. This hinged, flat bar style will be able to support heavy loads across spall spans. However, if the span of such a drain would increase too much, the bars would begin to deform under the weight of pedestrian loads.

flat steel grating, steel hinged grating, steel bar grates

Note that the hinged grating above is galvanized. Galvanization has two purposes in this situation. First, galvanization helps protect the underlying steel from oxidation or rusting. Singapore, being an island, is surrounded by salt water. Just the proximity of the ocean to a moist, humid atmosphere creates a corrosive environment. This, by itself is a reason to galvanize steel grating. A second, though minor, reason to galvanize is for slip resistance. Galvanizing imparts a coating on steel that is offers a degree of natural slip resistance, especially after initial oxidation. Chances for slips and falls are reduced by having that little extra abrasiveness on the drain cover.

Stainless Steel Grating

Another common trench grating material that has good resistance to corrosion is stainless steel. I found a good assortment of stainless steel bar grating throughout Singapore. All were in public places near subway stations and tourist sites. Again, all the trench drains that used the stainless steel grating were formed in place to accommodate the adjacent stone laid walking surface.

The photo shown below is my favorite Singapore bar grating. This is a simple welded stainless steel grating made of 3/8” square stock. The support bars are made of 3/8” square stock, as well. The spacing of the bars leaves an opening of ½”. The grating is resting between stone pavers and handicap pavers on a cast in place trench. The location is a sidewalk within a large park called “Garden by the Bay”. It’s a nice product in a world class park.

Garden by the Bay, trench drain system, stone paver trench drain, cast in place drain

Another example of heel-proof bar grating was found at an entrance of an elevator leading to the observation deck of the Sands Marina Bay Hotel. (See below.) This was an amazing hotel with a spectacular view of the city and the bay. Consider staying here if you travel to Singapore.

Marina Bay Sands, stainless flat bar grate, steel grating, steel bar drain grate

The grating was made with 1 inch wide stainless steel bar stock with the wide edge exposed to foot traffic. You can see the steel supports beneath the flat bars at about 4 inch intervals. This is needed because of the lack of rigidity the bars have when laid in this orientation. Each grating did have a 1/8th inch trim band surrounding the entire grate which helped to make it stiff.

An alternate to making heel-proof bar grating in the fashion, is to set the steel bars on edge. The photo below shows 1/8th inch thick bars set on edge with 1/8th inch openings.

heel-proof stainless grate, heel-proof steel bar grate, heel-proof grate, train station bar grating, Sentosa train station

Again, supports are beneath the bar assemblage at 4 inch spacing. The bars on edge make a stronger, more rugged grating that is both elegant and functional. With 50 percent open area, this grating will be able to handle the daily rains of Singapore. This particular stainless steel cover is at an elevated train station at the resort island of Sentosa. It is a grating style commonly used in bank and store vestibules.

Slotted Drain Covers

The final two drain covers to be discussed are the slotted drain cover. These are new to me. In fact, I don’t recall seeing this type of cover in the United States. They must be used elsewhere in the world, though.  These slotted drain covers are solid trench covers which sit in the opening of a trench drain as a grate normally would. However, to accommodate drainage, they have a single slot in the center of the cover running parallel to the trench. In these cases, they are unique because they also are designed to accept inlays stone or tile to match the surrounding walking surface.

The first cover, shown below, was part of the hardscape around Universal Studios on the island of Sentosa. The covers are approximately 12” x 12” with the center 1/3 of the cover devoted to drainage. The steel bars of the grating and the inlay frame are galvanized to help prevent oxidation. The remaining two outer thirds of the cover are used to hold inlaid stone and epoxy mortar that match the surrounding walkway. The trench drain channel seems to be formed in place and has a neutral slope. (Note the standing water when you look through the grate.) The cover is attractive, ADA compliant, heel-proof and is able to handle the high rainfall of Singapore.

stone inlay cover, grate with stone inlay, tile in frame grating, Universal Studios Sentosa

The second cover, shown below, sits at the base of a stairway in the subways below downtown Singapore (Also, an awesome subway network.) Though similar in design as the Universal Studio slotted cover, these covers were made with stainless steel and sported only a single slot. An epoxy bonded concrete was used as inlay around the slot. Each cover was about 12” wide and a meter in length. As this was in a low water flow area, only a single slot was required. Still, the cover spanned a large trench, which leads me to believe that the trench could also be used for conduit or piping, as well.

slot drain, high capacity slot drain, high volume drainage, steel drain cover

What an interesting study of bar grating!!! I did not find much variety of steel bar stock in the grating products found in Singapore, but what contractors did with the bar stock was incredible.  In the U.S., we have many styles of steel and aluminum bar stock used to make grating. Serrated, I-Bar, rectangular and riveted bars become part of the vocabulary when technically discussing bar grating here in the States.

Only rectangular steel bars were used to make the grating reported in Singapore. Stay tuned for Part 2 of this report, which will show more product variety as we cover cast metal and stone based grating observations.\

If you have any questions about the blog or the types of drains I’ve talked about today, leave a comment or email me at  For purchase inquiries, please call a Trench Drain Systems specialist on their toll-free line: 866-570-2333.

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Horse Barn Drain Installation – Econodrain #4

This is a story about a trench drain installation in a horse barn.  In this case, a drain was previously installed and deemed inadequate for many reasons.  The owners decided to replace the old drain with a product called Econodrain #4Econodrain is what I call a former trench drain system; it utilizes a disposable form to mold the channel shape in concrete.  I have written about this system in a prior article where Econodrain #8 was installed in a driveway with heavy water flows.   In this horse barn, they were seeing similar flows and needed a drain that could handle the volume.

Phase 1 – Initial Site Visit

The barn is situated slightly downhill from the rocky crest of a horse pen.  When it rained, water followed a natural path to the north door of the barn and continued downhill through the south door.  In an attempt to stop the flow, the owners had hired a contractor to install a trench drain at the north door and a catch basin in the center of the barn.  That contractor connected a pipe to each of these that was supposed to drain to a lower drainage outlet.  Asphalt was laid for the flooring material, covering the gravel layer that contained the plumbing.

Let me just preach a little about contractor selection here.  When you ask a paving contractor to perform a plumbing project or estimate the flow requirements for a landscape drainage problem, you are usually asking for trouble.  Not always, but usually.  For these applications, speak to someone that knows something about drainage and can help you design the system.  After that, a concrete or excavating contractor – maybe even a paving contractor – can usually do a good job at the installation.

There were three problems associated with the horse barn drains when we came onto the scene.  First was the drain selection.  The original contractor decided to take the easy route; he went to Lowe’s and purchased the first product he saw, which was the Spee-D channel by National Diversified Systems (NDS).  Spee-D is an all plastic trench drain system that is meant for pool and sidewalk applications.  The 2″ outlet that this drain has can only effectively handle 12 gallons a minute.  The barn was seeing 3-4 times the amount of run-off water that the little Spee-D drain could handle.  In addition, the water was heavy with sediment and the openings on the grates were becoming clogged, making drainage even less effective (see photo below).

A second problem was the drainage pipe used to drain the water from the trench.  The contractor used 4″ corrugated pipe rather that 4″ sewer and drain pipe (S&D pipe).  S&D pipe is smooth lined and more rigid then corrugated flex pipe.  In the process of backfilling corrugated pipe and compacting the gravel in the previous installation, we found that the contractor smashed this pipe, which constricted the flow, making water drainage even more difficult.

Lastly, and even more ridiculous, was the drainage outlet to this system.  In the process of digging the trench for the drainage pipe, the contractor found an old French drain and decided that was a suitable place to connect his outlet.  For those who want more background on French Drains, we have an article on that topic.  In effect, the drainage water was put into a small perforated  pipe that had no outlet.   So, in summary, a system that was designed to handle 12 gallons/minute was subjected to a flow of 50 gallons/minute.  Even so, it couldn’t handle the limited flow due to a crushed pipe and no outlet.  No wonder the barn was flooding!!

Phase 2 – Installation

I like pictures.  A picture says a thousand words.  Just go to McDonald’s and stare at the menu.  You don’t need to read anything; just look at the pictures and feel yourself salivate.  I’m going to do the same thing here – without the saliva.  You’ll see a few pictures in succession that show the steps of the installation of the Econodrain #4 trench drain system.

To preface, my assistant and I had to remove the old drain.  We began by cutting the asphalt, excavating the soil and removing the old, ineffective pipe.  Then we installed the new drain and piping, backfilling with gravel, and poured a final topping of concrete.  The photos below show the sequence and are accented with brief explanations.

First, we laid parallel chalk lines in the center of the barn, 12 inches apart, and used a concrete saw to cut the asphalt at the markers.  The asphalt was only 3 inches deep and easily cut and removed.  At times, the water from the saw blade washed away the chalk lines, so other markers had to be used to complete a straight cut line.

The existing drain was completely removed.  Once cut, the asphalt between the plastic drain and the barn yard was easily removed and stacked up for later use.  Similarly, the gravel beneath the asphalt was also removed and stored.

I didn’t get a photo of the piping installation.  As usual, the concrete truck arrived before the piping was completely laid.  That means there was a lot of rushing around and not enough time to take photos of the pipe setting, backfilling, the tamping of the backfill or the concrete pouring.  Actually, we could have used a third person for this part of the job.

We used standard concrete tools for the installation of concrete around the drain and over the drainage pipe.  The pour would have gone much smoother if we had a pencil vibrator, but no matter.  We applied some good ol’ fashioned elbow grease and got the job done.

A new catch basin was installed in the square cut out.  Generally, I make four inches of concrete perimeter around any catch basin.  For more information on catch basin installation, view one of the previous posts that have been written on this topic.

The concrete was poured level with the asphalt surface of the barn.  I didn’t really like this idea.  I would have preferred to have the concrete a few inches below the finished floor and then use asphalt for the last couple of inches.  However, for cost and time issues, the owners wanted to go this route.  They planned to power wash and seal coat the entire floor with a black bituminous coating anyway.  That would have covered up the color difference.

Phase 3 – Site Cleanup

The aftermath of a concrete pour is a sight to behold.  There is always a big clean-up on the following day.  This was the condition of the pour on the day after.  Not shown here are places where the horse and dog stepped in the fresh concrete.  The owners tried to smooth the concrete with garden tools but didn’t quite manage it.  I think it gave the appearance a unique charm.

After grinding off the 3/16″ spreader bars, the form was removed from the trench.  Because a mold release was used on the form surface prior to pouring concrete, it was easy to remove.  At this point, my assistant and I patched any blemishes within the trench with mortar.  The steel grating rails were scraped and wire brushed to remove dried concrete.  The channel was swept clean and made to look presentable.

Cast iron grates were finally put in place and fixed with locking devices.  These grates had a large open area to allow water to quickly descend into the drain body.  Also, as the grate was made from cast iron, there would be no problem with grates breaking under the weight of a horse or tractor.

We still had some trenching to perform and some pipe to lay downhill from the barn.  We were able to recycle some of the asphalt chunks excavated the day before into the backfill around the drainage outlet.  Instead of bringing the pieces to a landfill, we layered the asphalt over the S&D piping to protect it from being crushed by tractors and then covered the area with dirt.  The owners finished by surrounding the outlet pipe (invert out) with stones in an effort to make it visible to folks that might drive through with vehicles.

With the construction area cleaned within reason, we poured water into the drain to verify that everything was pitched correctly and flowing freely.  The owners still had plans to bulldoze the ground in front of the door level but finally had a drain that worked.  Our job here was done.

Trench Drain Systems is happy to have brought you this article.  If you have a question about trench drain installations or the Econodrain trench forming system, email us at  To discuss your application with one of our sales professionals, call us at 866-570-2333.

EconoDrain – The Versatile Poured-in-Place Trench Drain System

I think it’s time to tell you about a product that is a bit of a secret in the marketplace.  It is one that I’ve been selling for years but have not written about until now.  It is simple, economical, sturdy and versatile.  I find myself recommending it more now that I have installed it a few times and have experienced the ease and speed that it can be assembled.  I’m speaking of EconoDrain, a patented concrete trench drain former system manufactured by MultiDrain Systems, of Barium Springs, North Carolina.

Two types of Poured-in-Place Trench Drains

First a little background on poured-in-place trench drain systems needs to be covered.  Poured-in-place concrete trench drains come in two flavors:

1)      Frame and Grate Systems (or Traditional Trench Drain systems) – which requires that the contractor build the trench form, usually from wood.

2)      Trench Drain Former System – In addition to a frame and grate, a former system utilizes a disposable, pre-sloped form (or mold) that is used to make the drain channel.

The end result of both systems can be similar.   Both trench drain types are used to build a concrete channel with an embedded metal frame that supports an engineered grating.  There are some differences, however, which are discussed below.

Traditional Frame and Grate System – I think of traditional poured-in-place trench drain systems, or frame and grate systems, as one that is purchased from a foundry.  What you are actually buying is some quantity of cast iron grates and some cast metal rails.  The rails are used for making a frame to cradle the grates.  Traditionally, trench drain grates made by a foundry in the US have been 2 foot in length.  The width of the grates will vary based on the flow requirements of the channel.  However, a historically popular grate width seen in the U.S. has been 12”.  The rails used to hold the grates are often 4 foot in length.

So, for example, if you were going to install a 16 foot long trench drain using this system, you’d first purchase 8 grates and 8 rails from an iron foundry.

Two common foundries that manufacture this product are Neenah Foundry and East Jordan Iron Works.  These companies make large gray iron and ductile iron castings used in roadways and sewers.  Other plumbing fixture foundries, such as Josam, Watts and Zurn, manufacture frame and grate systems which are geared more for interior uses, such as maintenance facilities and warehouses.  Though there are differences in the design of each of these products, there is a great deal of application overlap.  And, in the end, each product requires a channel form to be constructed out of wood.

The act of building a wooden channel form can be a daunting task to the novice.  The wooden form is constructed and suspended in an excavated trench.  The metal rails of the drain are attached in some manner to the wooden form.  Because the rails are designed with an anchoring system, once concrete is poured around the form the rails become imbedded in concrete.  The wooden form which forms the trench is removed once the concrete is dry.  If a sloped trench bottom is wanted, the form can be constructed to produce the effect, or a mortar layer can be applied afterwards to slope the trench bottom.  It all sounds difficult.  But, it can be done in time with a skilled tradesman.

Trench Former System – A trench former system is similar to the traditional frame and grate product in-so-far that you are supplied a frame and grate.  However, with this type of system, you are also given a disposable, pre-sloped form.  The forms are specifically designed to attach to the frame, making the whole “wooden box construction episode” obsolete.  The forms and frames are assembled quickly and suspended in the excavated area by use of rebar.  As the frame and form are pre-engineered to a specific width and depth, less design work needs to be done in the field and installations are significantly quicker.  Forms are pre-sloped and can have rounded bottoms to give the resulting concrete channel improved flow characteristics.

The three most popular Trench Forming Systems on the market today are:

a)      EconoDrain (MultiDrain Systems) which uses an EPS mold to make round or flat bottom, pre-sloped channels that range in width from 4 inches to 24 inches.  The frame design allows the trench installation to be done with one concrete pouring event.

b)      Trench Former (ABT, Inc.) which also uses an EPS mold, offers channels that range in width between 6 and 24 inches.  Like EconoDrain, they have a patented framing system.  However, for proper installation of the Trench Former System, two concrete pours are required.

c)      FastForm (ACO) which uses a cardboard molding material to form the 12” and 24” wide channels.   Form assembly is required.

EconoDrain – The Most Versatile Trench Drain Former Product

Of the products discussed above, no one has a product that is as versatile, easy to install or cost effective as EconoDrain.  EconoDrain has a patented frame and channel forming system that eliminates the time and materials required in building a traditional formed-in-place trench drain.  The frames, which come in 8 foot lengths, have specially designed anchor stand shoulders that accepts #4 or #5 rebar.  This rebar is the supporting member that suspends the frame and EPS foam in the trench where the concrete channel is to be formed.

Attached to the underside of the frame is a lightweight, pre-sloped form.  Where traditional forms are made of wood, the Econodrain form is made of expanded polystyrene (EPS).  This form is designed with a locking collar which holds the form in the frame during installation.  The center wedge, designed with “ears”, is easily removed after the pouring and setting of the concrete, allowing the remainder of the form to collapse and be removed from the channel.  Thereafter, grates can be placed into the frame.  Locking devices are also available to help secure the grates in place.

The EconoDrain former system can be made with painted steel, galvanized steel, stainless steel or aluminum frames.  The most common grating options are ductile iron slotted grates and bar grating.  However, with the help of a company called Trench Drain Systems (, custom trench drain can be designed to meet your needs.  Custom stainless steel grates, decorative cast iron grates and custom polymer concrete grating (Jonite Grates) have been used with Econodrain.  Recently, MultiDrain and Trench Drain Systems have developed a pre-sloped, radius channel drain using custom forms made by EconoDrain.  These channels are used to make curved drains that can be used in running tracks, pools, driveways and fountains.  They utilize custom cast iron radius grating that cover curvatures that range from 3 feet to 55 feet in radius.  No other product or manufacturer can offer this degree of versatility in a poured-in-place trench drain system that can be achieved with Econodrain.

EconoDrain Installation Example

I recently installed a concrete former system trench drain in a home owner’s driveway.  Usually, in residential driveway trench drains, I recommend a 4 inch wide polymer concrete trench system (such as Polycast 600).  In this situation, however, a “river” of water was flowing down the driveway with a force that was moving yard structures.  A wider, more industrial trench system was required to divert the water.  We decided on using an 8 inch wide, poured-in-place concrete trench drain with a 10 inch wide grate containing a high percentage of open space.

We decided to place the drain at the bottom of the drive along the area we have marked with the measuring tape (see right).  We decided to direct the water to a cobble stone lined creek to the left, just behind the flowers.  The asphalt driveway was cut using a walk behind concrete saw.  The asphalt topping and soil was removed to a depth that allowed us to have 6 inches of concrete all around our form.  The drain frame and form was set in the excavation using #4 rebar.  I never took photos of these steps because I was busy getting the drain set.  The concrete truck was scheduled to be there soon!!

The photo to the right shows the drain just after we had placed the concrete.  We made a box to form a square end to the outlet end of the drain.  At this location, we connected a piece of corrugated pipe which ran below the surface of the cobble stone creek.  We let the concrete set overnight and removed the form the next day.  To remove the form, we had to first cut the metal support bars that hold the metal rails to their dimension.  For this we used a small angle grinder.  The EPS form actually seats around these bars during installation helping to hold the form in the frame.

Once the support bars were freed, a center wedge section of the form was removed, allowing us to pinch and collapse the remainder of the mold away from the new concrete channel wall.  The mold separated easily from the concrete because we had used a mold release agent on the form prior to pouring concrete.  After the EPS forms were removed, we cleaned the excess concrete from the metal rails with a scraping device and then swept the remaining dirt out of the drain.  The only thing left was to install the grates and bolt them into place (See below).

For more information on the EconoDrain trench forming system and how a system can be designed for your application, contain Trench Drain Systems (TDS) by calling 610-638-1221 or by emailing your request to