We make custom game mats for our intro/demo/convention games using a technique sometimes called “caulk & flock” mats. Here’s how.

Recommended Materials

  • Muslin fabric, unbleached.
  • Acrylic or similar caulk in a desired shade of brown.
  • Ballast in browns and grays, relatively fine grain not powder.
  • Flock and static grass, we recommend NOCH because 1) we like it and 2) we sell it in a wide variety.
  • Finely ground clump foliage.
  • Acrylic paint for rivers and streams.
  • High gloss transparent medium such as DecoArt Triple Thick or Liquitex Acrylic Medium (or both).
  • Clear matte/flat spray sealant.
  • A chalk line (as is used in construction).
  • An assortment of permanent marker colors.
  • A caulk gun.
  • Paint brushes for painting rivers.
  • A large-ish, soft paint brush for sweeping material off rivers.
  • 1/4″ and 1/8″ blue painter’s tape.
  • Transfer Pipettes (sometimes referred to as eyedroppers but much longer than you’d think) for pouring waterways.
  • Some tools for spreading and manipulating the caulk, we recommend popsicle sticks, the small wooden label sticks you can use to label potted plants, and a small blade metal putty knife.
  • A dust brush and pan set is also very useful.
  • A large catch pan, something like a wash tub.
  • A plan.

The Plan

For our example game mat we intended to recreate the road and river networks of the Battle of Eckmühl featured in our ESR Campaign Guide The First Battle Lost, 1809 in Germany. You don’t need to choose a historical map for your game mat, you can totally make one up, but we find that using a historical one innately gives us a realistic density of roads and rivers for a given geographic region.

Additionally, don’t be scared of using a historical battlefield map. We will be using our “Eckmühl mat” almost exclusively for generic, fictional engagements. Simply by moving around the hills, woods, and built-up-areas it is very easy to turn a specific map into a game mat that plays differently every time.

Obviously the first step is to measure and cut the fabric to size. We use muslin fabric because it is very low weight and has very good drape, thus placing hills underneath it later will be easy and the fabric will largely conform to our hills and elevations. Our map is 9×6 miles and we are going to create our mat at 1″=150 yard scale, which means one foot is one scale mile, so, a 9×6′ game mat. All of the maps in our Campaign Guides have a grid overlaid dividing them into one mile by one mile squares. Once the fabric is cut we use a chalk line to replicate the 1×1 mile grid on the fabric.

The Preparation

You can also see (at the bottom of the photo where the chalk lines stop) we’ve lined our work surface with white butcher paper. This is because when we smooth the caulk and impress flock into it some will naturally permeate the fabric and we want to keep our work surface protected.

Once the grid is in place we’ll transfer the rest of the road and river network to the mat using different colors of permanent markers.

We used red for the main road, black for the minor roads, blue for the main rivers, and green for the minor streams. The corresponding grids make it easy to transfer these from our source map to our game mat accurately. The different colors reduce the likelihood of error when we later paint in the waterways and begin to caulk the roads.

Waterways: Initial Steps

In real life rivers and streams are rarely blue, more commonly they are greens and browns depending on what the surrounding soil is, the clarity of the water, speed of flow, etc… For our mat though, we are primarily concerned with visibility and discernment. We want our players to immediately see and identify the waterways and be able to discern between both them and the surrounding terrain but also each other since we are doing two different grades of water hazard. Therefore we are picking brighter colors that are bluer than is realistic but which will serve our purposes well.

Once all of the waterways have been painted and allowed to dry, we double checked the intersections with the roads and touched some up to coverup any of the permanent marker lines that bled through. With that complete, we applied several … thin coats of Liquitex as an intermediate seal coat. Basically applying it, allowing it to dry, and doing another coat, until we achieved the sheen visible in this photo. It is important to note here the purpose of this step and why we used Liquitex.

Sealing the waterways before doing any caulk work is very important. Caulk and flock will stick to the painted waterways and not come off cleanly without a sealant layer. The primary driver for using Liquitex was the time of year and weather which prevented us from doing this step outside in a well ventilated space with a different product. In the past we have used a high gloss spray sealant, but our design studio does not have ample ventilation for doing so and it was too cold out spray outside.

Roadways

With the rivers sealed we move onto road ways and our first caulk work. The process is simple: lay down a narrow bead of caulk using a typical caulk gun and spread/smooth it out to the desired coverage area. Our roads are very narrow because of our high ground scale – about 1/4″ wide for our minor roads, and about 1/2″ for our main road. It is important that you don’t put the caulk down too thick as when you pour the ballast over the top and then press it into the caulk, you do not want the road to widen more than intended. Once the caulk has dried you can pour the excess ballast off the mat and into a catch pan to be used again on a latter project.

Here you can see the stages of ballast-ing the roads. In the first step, it is important to quickly pour ballast over the caulk after it has been spread. This is because immediately after being exposed to air the caulk will begin to dry and skim over. How long it will stay workable will vary based on temperature and humidity, but ultimately it is important to cover the caulk with ballast (or later flock) before it has skimmed over. If you’re unable to, you should disturb the skim to expose the still wet caulk beneath or you will not get good adhesion. On larger areas that you’ll be flocking later, it is also practical to add more caulk if you run into this situation.

Ideally it is best to have two people working together, the first lays down the caulk bead, the second smooths and spreads it, and then the first pours ballast over the top and presses it down into the caulk.

Using a spoon to pour ballast works well so that you can maintain control but also ensure ample coverage. Pressing the ballast into the flock is most easily done with your hands, though you can use a flat object to evenly press it in, such as a small sheet of cardboard. Be aware that as you do so, you will reveal thin spots and need to add more ballast, this is perfectly normal.

Here you can see two previous sessions where roads were laid (the main road and some minor roads) as well as the current session where the caulk is covered in excess and drying.

At this point you’re likely to encounter something that will drive how fast you complete this project. Because it is necessary to put so much excess ballast or flock into the caulk that you can’t recoup until the caulk has dried, what determines how much progress you can make in each caulking session is going to be primarily driven by how much material (ballast or flock or static grass) that you have.

Reflective Pause

Every so often it is important to pause and look at your progress. Yes, the road network around Eckmühl in 1809 is just that crazy and insane looking, but remember, that grid of faint blue chalk lines indicates one mile by one mile squares, so it is actually very low density compared to ya know, nearly anywhere we travel today.

The First Flock

Exactly how you caulk and flock your mat is going to depend on your plan. If you are doing a mat that will ultimately have a sparse road network, then we’d encourage you to self-limit the size of areas you flock at one time to be no larger than 12″ by 12″. This is because of what we’ve found easiest to manage and how fast caulk tends to skim over and lose the initial adhesion necessary to get flock amply smashed into it. Again, this will vary based on humidity and temperature, but even in warm, humid environments, we find that larger than 12″ by 12″ areas is simply not as effective.

Laying a small bead of caulk around the inside of an area fenced in by roads works well on our mat because of how extensive the road network is. After a bead is laid down, we use a small wooden tool – in this case a small wooden stick normally used to label potted plants – to spread that caulk right up to the road, basically filling the ~1/4″ gap between the road and where we laid down the caulk bead. This is to prevent accidentally running fresh caulk over the top of a road by accident with a larger tool. Once we have that outline done we add more caulk and use a small metal putty knife to spread it and fill in the entire section. These are both tasks that should be done quickly to prevent the caulk from skimming over.

Once this area is fully caulked, let’s get to flocking!

Next Verse, Same as the First…

Really, this is a step that will take a lot of sessions. Each one limited by your available time, your available flock, and the size of your workspace. Our work surface was only 9×5′, but our mat is 9×6′. Which meant that we always had ~18″ hanging off one side that would need to be done after the on-surface portion finished drying and we dumped the excess flock off.

The First Return to Waterways: Tape

Once all of your road-only sections are caulked and flock, large portions of your mat, those that are fenced in by waterways or a combination of waterways and roads remain. For our mat we had decided to border all of our waterways with clump foliage. We did this for two reasons: 1) to further differentiate the waterways from the terrain around them so they were immediately recognizable, and 2) because we thought it would look cool. On previous mats we did not do this and we found that rivers and streams would sometimes seem to blend away into the mat (NOTE: they were also more realistically colored on those mats). So on this mat we wanted to try something new. If you’re not going to line your waterways with clump foliage and just flock up against them, then you should slip this step entirely.

We used 1/8″ and 1/4″ blue painter’s tape to mask off the edges of our waterways. The 1/8″ tape was used first to mask off the waterway because it is so flexible in turning and twisting to match the streams and rivers, while the 1/4″ was then used overlapping the 1/8″ to provide a “buffer” between the waterway and where we will stop our flock. This allows us to flock right up against the tape without intruding on the waterway and will ultimately provide us a space to put down the clump foliage we will border our waterways with.

It is important to leave “tags” of tape free at each end and intersection of the tape runs so that you have a place to pull the tape from without digging your finger into the caulk and disturbing the flock. It is also important to pull your tape immediately after you are done laying the flock down and pressing it in. This minimizes the amount of caulk that is pulled up with the tape because the drier the caulk is, the less it cleanly separates from itself. Lastly, it is wise to press the flock into the caulk again after you’ve taken up the tape to ensure the edges are well covered.

Fourth Verse Same as the First…

We’re in the home stretch at this point, once we’re done flocking these sections we’ll only have one more caulk related step.

Hedge Time

As mentioned earlier, we wanted to give a unique look to our waterways by lining them with clump foliage to visibly show the rough terrain around the banks of the rivers and streams. It is important that the foliage is ground fairly fine.

By its nature it will breakup and tear when pulled apart. We want this clump foliage reduced to effectively the smallest clump that no longer easily breaks part, otherwise, those bits will breakup after being attached to the mat and the result will be thin and bare spots.

It is important to use a very thin bead of caulk. Since both sides of the hedge space area already finished, there is nowhere for any extra to go and extra caulk is at risk of covering over your waterways.

Similarly, it is very important to really smash the foliage into the caulk as much as possible to assure good adhesion.

You’ll also notice that throughout this portion we hedge one side of the waterway, allow it to dry, remove the excess, and then hedge the other side. We found this the most successful workflow to not accidentally disrupt the opposing riverbank.

Once you have the foliage in place, you can use a large, very soft brush to “sweep” the river clear of foliage and ensure that the waterways were not accidentally covered.

After the caulk has dried, you can pour off the excess foliage into your catch pan just as you did the flock and ballast before it.

At this point it is also good to use a mini-dust pan and dust brush to gather foliage off the mat. This allows you ‘sweep’ the portions where you have a lot to remove with the least impact to other areas. Some flock will continue to come off naturally so be mindful.

Another Good Pause

This is another good time to pause and consider the progress. The next steps are to seal the flock and pour the waterways.

Here you can see the minor raised visual effect that the hedge lining of the waterways gives. It provides a minor 3D effect to a mat that is necessarily two dimensional before other terrain is added to it for a game.

Sealing the Flock

On previous game mats we have 1) stopped at this point and called the project complete. We found with those we had significant flock loss over time. While thin spots and bare spots honestly don’t look bad because of the underlying brown caulk, this was still not what we were aiming for. On other previous game mats we have 2) attempted to help adhesion by applying a coat of hairspray – yes, literally hairspray. But, as one might expect it only had a modest impact. In both cases we found that static grass was far more likely than flock to ‘wear off’ over time through friction when the mat was folded and transported. For this mat we decided on a new solution: flat spray sealant.

Despite the season we are now semi-commonly granted by the fate of climate change a handful of unseasonably warm days during the winter. We were hopeful one or two of these might align with our need to spray outside because we’d had a very mild and warm winter this year. And, the week we needed the warm temps, they happened. Taking advantage we laid the mat out flat on pavement and sprayed two coats of flat transparent sealant on the entirety of the mat.

The result of the spray adhesive/sealant has been fantastic. Normally, each time you manipulate the mat, roll it up (we’re avoiding folding this one but more on that soon), lay it out, etc… you’d dump some flock. After having apply the two coats of spray sealant that has dropped to as close to zero as we can reasonably expect – and note, this mat was hauled from Saint Paul MN to Milwaukee WI and back for AdeptiCon 2025 where it was used to run seven games of ESR Napoleonics. So it has already seen a bit of travel and use.

A Last Return to Waterways

One key thing about the spray sealant being flat or matte is that it removed the gloss the Liquitex had added to our waterways. Now remember, the primary purpose of that was not appearance but rather sealing them so that rouge caulk was easily wiped off. However, as an end result we do want rivers that reflect light and appear to have at least a little depth. This is where we turn to ‘DecoArt Triple Thick High Gloss’, which as best we can tell is just a high gloss acrylic medium, albeit very thick.

We used “pipettes” to pour this medium into our rivers and then a small paint brush to ensure it spread the full width of the waterway. This changed the appearance of our painted water some – in good ways: 1) it became radically more glossy and showed a small amount of ‘depth’ even while being a thin coat, 2) it distorted the surface slightly so the paint beneath looked less clear – much like actual waterways. We applied this medium very thin in two coats and recommend against going thick. The viscosity of this particular product is such that it is very easy to control and spread as you like. However, keep in mind how you will store your mat. The tests we performed on test fabrics showed that folding will leave crease marks in your poured waterways and can result in cracking. The thinner the medium is put on the less this occurs, so a balance needs to be struck. Secondly, we strongly recommend rolling mats like this but especially those that include poured waterways.

Photographing the poured waterways to show off the effect of the medium has proven difficult, they don’t look bad in photos but they look radically better in-person.

Our new game mat debuted at its first convention in Milwaukee at AdeptiCon 2025 and it was a smash, numerous people stopped to take photos, ask questions about it and ESR Napoleonics, and all of our 42 gamers across our seven events voiced compliments and positive impressions about the look of the game. What’s the big take away? Given some time and materials, you can make what we did.

Questions?

There’s an FAQ immediately below, but you can also jump into Discord to discuss further!

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Frequently Asked Questions

Question: How were the hills done?

Answer: Literally cloth rags. Like washcloths, re-useable shop rags, old hand towels. They are always the right size and right shape because they are so pliable.

Question: Where can I get those trees?

Answer: The trees are by NOCH, a German company that specializes in model terrain mostly targeting scale modeling and model railroading – and we sell em! We also sell their flock and static grass products that were used to create this mat.

Question: What about the bridges and buildings?

Answer: The buildings we used to import and sell, they are from a small UK company, however, they pulled back from the US market during Brexit and the pandemic. The bridges are ours! and we’re about to release them for sale. Assuming you like them we are also investigating doing our own line of buildings and built-up-area tiles.

Question: Does the sealant stiffen the fabric?

Answer: Yes. Muslin, as we mentioned, was chosen because it has such great drape due to being lightweight and therefore it conforms to our “hills” very easily. However, once you spray two coats of sealant on it, it does stiffen – not as much as if it was other fabric, but it is noticeable. Our solution to this is to put a layer of foam tiles (like would be used in a home gym, a convention exhibitor booth, or a kid’s playroom) on our gaming table, place our mat and rag hills on top, and then pin the contours of the mat into the foam tile, using literal pins, like you would for sewing. It works exceptionally well and it prevents your hills from changing during the game as well due to someone bumping or moving something on the table.

Question: How much ____________ did you consume making this mat?

Answer: Excellent question! Our example mat is 9×6′. Obviously material consumption will vary with mat size.

  • Caulk: Twelve 10 fl oz tubes (two for roads, one for hedges, nine for flock and static grass).
  • Flock & Static grass: approximately 600 grams.
  • Ballast: We failed to measure as we were using left over material from past projects.
  • Foliage: Same problem as ballast, this was left over from past projects and we failed to measure it.
  • Paint: Most of two 2 fl oz containers (~2/3 of each color).
  • Liquitex: We used more than we might have needed to just for a sealant layer and if this were done in warmer weather we’d have instead used a single can of gloss spray sealant, but we consumed less than one 8 fl oz container (estimated 3/4 consumed).
  • DecoArt Triple Thick Brilliant Brush-On Gloss Glaze: ~9-10 fl oz (it is sold in 8 fl oz containers).
  • Painter’s Tape: 3+ 22-yard long rolls of 1/4″, 2+ 22-yard long rolls of 1/8″.

Remember, while we only consumed 600 grams of flock and static grass, the amount of excess that you pour on and then pour off into a catch pan is massive, so despite only consuming 600 grams, we “temporarily used” most of 1440 grams based on the variety of containers we opened to apply different colors and mixes.

Question: How long did this mat take?

Answer: We did this mat in a series of sessions due to required dry times. Again, our mat is 9×6′ and a smaller or larger mat will very. Other things that directly impact the time are more flock/static grass colors will increase the number of sessions you need to do (and fewer will lessen them), and a larger work area – our work area at the time was 9×5′ so we always had a minimum of two sessions for each “color” of static grass or flock in order to do the portion that was hanging off. We didn’t track our time exactly, but we believe it averages out to one two to three hour session per day for 3-4 weeks. The reality was more complex. Some sessions (like drawing the map on the fabric) were very fast and completed in ~90 minutes. Others were very long, some of our flocking sessions went a little over three hours. If our work area had matched our mat size we’d have been able to do fewer sessions but each session would be a bit longer.

Question: How many terrain mats have you made?

Answer: To-date? This is our fifth. We intend to produce another one for Historicon 2025 later this year.

Question: Will you ever sell terrain mats?

Answer: The amount of labor is such that it does not make sense to sell them as a product, no one is going to want to spend thousands of dollars for a single terrain mat. We do intend to sell those that we no longer use at a more reasonable price and will first offer them up to Friends of the Pen-Gin™, and then to the general ESR Napoleonics community to find them a new home.