Introduction: Building a Haunted Chapel
This static Halloween decoration was made from 57 sheets of EPS White foam of various thicknesses. The design was based on a real Chapel in Scotland (Ardgowan) and designed using Sketchup. It was built in 4 months working every weekend and some evenings from June - September so that it could be up by October 1st with the Halloween display.
Each section was cut by hand and glued together and built to be easy to assemble. This chapel after constructed takes 4-5 hours to assemble.
Note: No woodpeckers were injured in the making of this prop.....but the prop was. Nothing a little A-B expanding foam could not fix :D
EPS White foam
Qty Thickness Material
6 - 2" 4x8
1 - 4" 4x8
4 - 6" 4x8
4 - 8" 4x16
27 - 8" 4x8
2 - 10" 4x16
4 - 10" 4x8
7 - 12" 4x16
2 - 12" 4x8
1 - 16" 4x8
14 boxes exterior foam coat
3 gallons Foam Fusion Glue from Hotwire Foam Factory
10 - 1 1/2" 10ft ABS pipe
7 - 2 1/2" 10ft ABS pipe
1 - 4'x8' 1/4" ABS sheet
1 55gal plastic barrel
1 drill pump
10ft garden hose
Demand Products Field Cut Hot Wire Cutter
Hotwire Foam Factory 4ft Bow and Hot Knife with Sled
Demand Products 16" Rasp
5 Gallon Exterior Latex House Paint
5 Gallons Medium Gray Exterior Latex House Paint
5 Gallons Light Gray Exterior Latex House Paint
4" Harbor Freight Paint Brushes
Water Spray Bottles
Watered Down Black Exterior House Paint
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Step 1: Design
When we were looking for a replacement facade to our ruined abbey we set up in our driveway as a backdrop to our cemetery display for Halloween we came across this photo of a ruined chapel and knew we had to build some version of it out of foam.
We used Sketchup to design the chapel scaling it to fit in our driveway and still look like the reference photo. The design had to be free-standing with no support structure, easy to set up and be stable enough to withstand being outside for a month in Oregon weather. We spent 2 years coming up with the design before we built it.
Step 2: Determine Materials Needed
After the SketchUp design was finalized we created a parts list to determine the materials we would need. We provided our parts list to our foam supplier and got a quote back that was more than double our budget.
The supplier suggested that we order the material in full sheets and that we cut out our parts ourselves which was within our budget but did require that we purchase a few extra tools for cutting and created a very large amount of scrap foam that we figured we'd use for other projects. Cutting out our own parts also effected our timeline for getting the project done. In order to have the chapel ready by October 1st, we needed to start on June 1st working every weekend and some nights.
We also saved some money by going with 8" thick walls instead of 10" where it didn't show. The number of 8" thick pieces saved us quite a bit on our budget so we could purchase the additional tools we needed.
Step 3: Ordering Foam
During the design phase, we had heard that we might be able to get 16ft long foam so we contacted our foam supplier and they said they could order it for us. 16ft x 4ft x 4ft is the largest (master block) we can work with.
This removed the need to have 2 - 8ft pieces connected together where we spaned over 8ft. With the longer sheets and a large number of sheets we couldn't get it delivered so we had to rent a 20ft truck and make several trips to the supplier to bring all the material back to our shop
Step 4: Cutting Foam
In order to cut all the pieces for the foam, we used two different techniques. When a sheet just needed to be cut to length we used the Demand Products Field Cut hot wire tool which will cut up to 55" wide and 16" deep pieces of any length and can cut smaller pieces at angles.
For the more complex cuts, we cut out 1/2" plywood templates for each edge of the cut and then used aHot Wire Foam Factory Router Bow attached to a VARIAC power supply.
We would clamp the templates to each side of the foam and with two people we would pull the bow over the template cutting out our patterns.
One of the design elements was that we wanted each wall to keep its full 4ft height even though they would be tongue and groove. If we cut out the tongue at the top we would loose 2" of the height of each wall. So we used the Hotwire foam factory industrial knife with a sled to cut a 4" wide 2" deep groove in the bottom of the wall and then cut out 4" wide strips of 2" foam and glued them on the top of the walls so they walls stayed at 4ft tall.
We used the same Hotwire Industrial knife and sled to cut the slots in the buttresses that were 8" wide and 2" deep to fit the 8" wide walls that fit into them.
Step 5: Laying Out the Foundation
One of the key elements of the design was that we wanted the walls of the chapel to be level at the top. Since the driveway has a slight slope to it we had to create a foundation that was shaped to the driveway. We used a construction laser level to mark the slope on the foundation pieces. We used the Hotwire Foam Factory Router bow to cut the slope off the bottom of each foundation piece. Now when we laid out the walls on top of the foundation they would be level at their tops.
Step 6: Holding It Together
Several pieces need to be glued together that couldn't be cut out of a single piece of foam.
The spire, the corner buttresses, The tower base (both square and octagon), all the tongues. Anywhere we needed to glue two pieces together we used Hot Wire Foam Factory's Foam Fusion. You will also need ratchet straps to hold the pieces together while the glue dries.
We often used the 50lb boxes of exterior foam coat as weights when gluing. Bonus!!!
Step 7: Boring Holes in the Foam
The design called for using 2 1/2" ABS pipe in 4ft lengths to attach the peak pieces (one in the top and 2 at the bottom) and 4 corners of the 3 sections of the tower. This meant we needed to bore 24" holes in 8-10" thick foam. These holes needed to be straight and perfectly aligned. So we built a boring box out of 1/2" plywood and 2x4s. We drilled 2 holes with a 2 1/2" boring bit that were perfectly aligned. We used a 24" piece of 2 1/2" ABS pipe and beveled the edge and cut out teeth all the way around the edge using a band saw. We attached the pipe to the hole saw bit for a drill and then used a corded drill to bore the holes in the foam using the wooden box as a guide to keep the boring tube level and aligned.
Step 8: Keyhole Connectors
Securing the walls together required a keyhole design.
We took a sheet of 1/4" abs plastic and had it cut into 24" x 24" squares.
Then we had a water jet service cut the keyhole pattern repeatedly into each sheet. The plates were cut out using a table saw.
We cut 1 1/2" ABS pipe into 12" pieces and glued a flange cap onto each one.
We used a piece of 1 1/2" ABS pipe with a beveled end and slots cut into attached to a hole cutting bit and used it with a hand drill to bore holes into the ends of the foam to insert the pipes and glue them in place.
The plates were installed using an industrial hot knife with a sled attachment with 2 blades. The first blade cut the deep groove and the second blade cut the 1/4" recess the plate glued into.
We used water-activated polyurethane Gorilla glue for both the plates and the pipes when gluing. This glue has tighter bonding strength than the Hotwire Foam Factory Foam Fusion we used for the rest of the project.
NOTE (AKA Learn from our mistakes): The original design shows 2 keyhole connects for each 4ft section. We decided to only do one connector per 4ft section towards the top of each panel. This was sufficient to hold everything together and made assembly much easier. Trying to line up the 2 keyholes on each side would have made things too difficult.
Step 9: Laying Out Stones
When laying out the stone pattern on all the wall surfaces we followed a known stone masons pattern below. We used sharpies, straight edges, and a Dremel Trio 1/4" router to make all the grove lines.
To assure that the structure looked like a real building we researched stone masonry. We cannot stress how important this is for a realistic design.
Ten Basic Principles of Stone Masonry
1. Try to lay sedimentary stones (limestones and sandstones) sotheir natural bedding planes (BP) are horizontal, not vertical with the natural cleft (NC) face exposed.
2. No stone should be laid taller than it is long, except at corners.
3. Avoid block or running joints only one stone on at least one side of a vertical joint.
4. Avoid setting more than three stones against a riser.
5. Risers should be evenly distributed throughout the wall. Grouping together of like-sized stones should be avoided.
6. Avoid using more than two stones of the same size on top of each other.
7. Unless by design, avoid the lining up of vertical joints in alternate courses.
8. Generally, risers should never touch except at corners and openings (jambs).
9. Don’t allow horizontal joints to run more than four or five feet. If possible, break up the horizontals on short stretches between windows and doors.
10. Try to provide a substantial bonding lap. A minimum of a quarter, and ideally a third, of the length of a stone being set, should cross the joint between the stones below it.
Step 10: Gothic Windows
Two windows are featured in this design. We researched gothic windows and found "Tracery" to be the answer. Your geometry classes pay off now :)
A smaller 24" x 48" window and a larger 48" x 96" windows. The smaller one was cut from 2" thick EPS from a hand-drawn design.
The larger was cut from 4" thick EPS foam traced from the Sketchup design onto a sheet of foam. The larger window was made with the larger design in one piece at the top and the legs and sill separate pieces.
The window designs were cut out using hot wire and then hand sanded and shaped.
Step 11: Texturing
To make the chapel more durable, we coated the foam before painting.
After the stone patterns were drawn on the foam, we laid out and routered we used a Demand Products Durarasp (a tungsten rasp for roughing up EPS foam) to break the smooth surface of all exposed foam. This helps the foam coat stick to the foam.
Use a broom or air hose to loosen the foam dust before coating.
Using a hopper sprayer from Harbor Freight we applied Exterior Foam Coat from Hotwire Foam Factory mixed with concrete dye. We mixed the foam coat with enough water to make it easy to spray but not too soupy. We added a small amount of black concrete dye to each mix so we could see where we sprayed.
It was important that we didn't spray any of the connecting areas (grooves or tongues) so they would fit into each other later.
Before spraying this required us assembling sections of the chapel with their adjoining walls or buttresses; so those areas wouldn't get coated.
Because the concrete dye wasn't applied evenly from batch to batch we ended up having to spray all of the pieces with black exterior paint to make them all even.
Step 12: Painting
After the chapel was cut we assembled it in pieces to start painting. We started with a base coat of flat black exterior paint applied with a paint sprayer to every exposed piece of foam.
Do not use spray paint as it will damage the foam. We use exterior latex paint we get from our local recycled paint company MetroPaint. We use their Black, Storm Cloud, and Misty paint colors.
The walls are then painted with two different shades of gray exterior house paint. The darker gray is first with a faux sponge roller brush. Use the roller to a coat of the dark gray paint to cover 80% of the black surface of the wall in small batches. Be sure to leave black paint showing in all the recessed areas. While the dark gray paint is still wet, take the lighter gray and cover over the dark gray about 50%. Then take a rag (I use an old washcloth or large sea sponge) and tap the painted surface over and over (be sure to change hands to alternate the pattern) to blend the two colors and remove the pattern left by the rollers. Let this coat dry before going to the next step.
We then 'aged' the prop. We do this with a mixture of water and a black exterior house about 50/50. Take a (squirt) bottle of water and spray where you want your drip areas to be and then take a small paintbrush with your watered down black paint and drip where the water naturally runs down the structure, with a large 4" paintbrush, feather out the edges and line to wipe down the drips so they look like weather washed stone and not dripping mascara stone.
This makes the structure look more weathered and worn.
Step 13: High Tech Part Tracking
Tracking 57 pieces of foam. To make setup easier, we used NFC cards with a descriptive string written to them embedded in each piece of foam. This ensures that during set up and takedown we know what piece goes where by just placing a smartphone near the card and reading the description.
Step 14: Setup
The chapel was designed to be easily set up.
Step 1 -The back wall is assembled with the (peak inserting 4ft 2 1/2" ABS pipes) and buttresses attached on the ground and barn raised up. We used wood "feet" to keep the edges from rolling (wearing away)
Step 2 - Assemble the tower on the ground by attaching the 4 sections with 4ft 2 1/2" ABS pipe we lift the tower upon its foundation base and fill a 55-gallon drum inside with water and add a little bleach to keep it clean.
Step 3 - Attach the walls that attach to the tower base. Each wall has a custom keyhole system in place.
Step 4 - The front wall with a window, peak (using ABS Pipes again), and buttresses are assembled and barn raised and attached using the keyholes
Step 5 - The sidewall is built stacking each wall section on top of each other as they attach into the buttress. The next buttress is attached and another set of walls attached going from the foundation upwards. The final wall is then connected to the back wall by raising the back wall up with a hand truck 6" to lift it into the place.
Step 6 - The corner walls are attached to the back wall. The buttress is attached and the entrance walls are attached by stacking on each other and their foundation.
Step 7 - The final key wall is inserted above the entranceway with 4 special cut keys to insert it into place.
Step 8 - Attach the 2 buttresses at the end of the entrance and set the peak in between them.
NOTE: To help to put the taller pieces together we use scaffolding from Harbor Freight. Watch sales and coupons to get the best deal, we used two of them.
Step 15: Final Thoughts
Our Halloween projects usually span multiple years and the chapel is no exception. There are several things we didn't get to the first year that will be on our list for the future.
- We didn't build the caved-in roof or a roof over the entrance. It is our plan to make beams out of foam and roofing material that looks similar to the reference photo.
- We didn't create stone lines or texture the interior walls. All we did was just paint it dark grey. We plan to do the same detail in the interior as well.
- We also didn't create broken stain glass windows. It is our plan to use plexiglass and create broken stained glass windows for both the big front window and the smaller side one.
Note: The drone footage shows a woodpecker who LOVES the chapel. He got a present from a family member. :D BTW - said bird is alive and well, and the subject of multiple social media posts
Eighth Prize in the
Halloween Contest 2019