Introduction: Hidden Cave / Play Room Fort

Picture of Hidden Cave / Play Room Fort

When I was a kid, we made a fort out of everything. We built a play house / fort in the woods with random stuff we found. We put together a cardboard box car, rocket ship, building, whatever. But we never had a play room to ourselves......

So, now that I have a son, I wanted a playroom or permanent fort just for him. The fun thing was figuring out where to put it and I found the perfect space, A triangular section above the dining room that is 3 feet at the highest point in the center and 11 x 14 feet overall. The problem was, to get to it, you had to crawl through attic space, over wires and open studs, and into a space with no lighting, windows, ventilation, or floor for that matter. Plus there are nails sticking through the roof sheathing..... So lets fix that.

Step 1: The Before Picture

Picture of The Before Picture

This is what the space looked like before.

Step 2: Materials and Tools

Tools needed:

Circular Saw
Cordless Drill
Shop Vac
Jig Saw
Tape Measure
Sharpie marker
Foam spraying equipment (just hire it done)
Temporary lighting
Electrical tools
Knowledge of electrical systems
Knowledge of supporting walls


Foam tiles
Spray foam
Great stuff foam
Window weather proofing
Permanent lighting
Electrical boxes/ switches/ outlets/ wire/ breaker
Electrical tape
Wire nuts

Safety gear needed:

Safety glasses
Safety goggles
Ear plugs
Respirator - dust mask and a half face OV/HEPA cartridge model
good shoes
knee pads are helpful
and Bandaids.....

Step 3: Cleaning Out the Space

Picture of Cleaning Out the Space

The house we live in is a century home. This means there is dust up here from 100 years ago, nasty coal dust from the old boiler, cob webs, animal stuff - we will leave it as "stuff", birds nests, mouse nests, garbage, and loose insulation.

So lets get rid of all of that and clean this place up a bit. A big shop vac should do the trick, as well as garbage bags, a dust mask, gloves, tons of soap, and a lot of time. I hired a neighbor kid for 10 hours to give me a hand. He swept stuff up, I emptied the shop vac when needed while working on construction on the rooms below, and he got some money he wanted to go on a Jamboree trip.

I used 3 sections of hose on the shop vac to reach back in here. Duct tape worked great to hold them together, with some couplings

I also used a IR remote on a outlet adapter so the neighbor boy could turn off the shop vac when it jammed, or he needed a break, which happened quite often.

Step 4: Adding a Window

Picture of Adding a Window

I need an escape route for my son if a fire were ever to break out. Who wants to be trapped in a small space with flames all around?

So I found this great window at my local Home Depot. The window unlocks with two big handles and pivots in 45 degrees. This would give great fresh air if he wanted it. The whole window can then be lifted out and set aside leaving just the frame left and a 14 x 28 opening to escape. I can fit through it with no issues so I know my son will be able to.

I cut through the outside of the home, braced the window in place, put weather seal tape on the outside and later this year, will be putting cedar shakes on the outside of this section of the house. It never was sided before, just had tar paper on it. as it is a small triangular jut out leading to a flat roof. With the flat roof outside, my son can at least climb out onto something and jump 8 feet to the ground or my arms if needed.

Somehow I can foresee getting a phone call from a neighbor letting me know my son is on the roof again. I am going to have to work on that being for emergencies only...... 

Step 5: Adding Lighting

Picture of Adding Lighting

Who wants to be in a dark cave with no lights? Ok, well maybe there are times, but overall that isn't a great idea.

I ran electrical power into the cave area and put 3 lights in the ceiling. The switch to turn them on is right inside the access door to the chase leading to the cave. The lights are construction strand lights I had laying around. I replaced the plastic cages with nice metal cages and put in LED bulbs for low heat emissions and a cool to the touch bulb if my son decides lights are shiny and fun to touch.

The lights are plugged into an outlet box at the ceiling level. This way if my son decides to sleep in the cave area he can turn the lights off from inside the cave and use a flash light.

Step 6: Ventilation

Picture of Ventilation

The cave area needs a source of fresh air. I didn't want to rely on leaving the small 16 x 16 door open and hoping air would make it through.

So I bought a little bit of duct work, a vent cover, an inline duct fan, and a duct versa cap to keep my son from putting things down the vent. No LEGO men allowed in the fan.

I cut a hole in the ceiling by the edge of the dining room, ran the duct and fan, and installed a white cover on the ceiling of the dining room.

The fan was wired into a plug end and plugged into the same box as the lights.

Not only does the fan provide the area with fresh air from the dining room below, it also provides me with a way to know my son is in the cave. The fan makes noise just like a bathroom fan does. So I know the lights are on and someone is in the cave. I also know if I see my son and hear the fan running that he left the lights on when he exited the play area.

Step 7: Flooring

Picture of Flooring

Half inch plywood was put down for the floor covering. It was also used to cover the floor in the crawl way leading to the cave (about an 8 foot crawl).

Luckily, I thought about doing this project when I had the ceiling open and under renovation in the room under the crawl way attic part. I was able to put a bunch of plywood in 2 foot and 3 foot wide sections up above for when I could finish the cave prior to the drywall going back up.

The plywood was screwed down to the floor joists to secure it in place.

A hole was cut for the ventilation duct to to through. The Versa cap on the duct makes it look a little industrial which I like and keeps the LEGO men alive and not blended by the fan.

Step 8: Insulation

Picture of Insulation

Closed cell spray foam insulation was installed by a local company called Pureseal. They installed the foam 5 inches thick on the ceiling of the cave and 4 inches thick on the walls. They also sprayed the walls and ceilings of the 3 rooms I had under construction below in the home as well at 4 inches and 2 inches respectively.

After informing the guy of what I was hoping to do with the area, he covered the studs as well with the foam to make it look more like a cave. They did an amazing job. And I have many other studs not covered for termite inspections in the future.

The insulation basically makes the room like a large Styrofoam cooler. the insulation value is about R- 30 on the ceiling, which is much better than the R-1 that was in there with less than 1 inch of blown in insulation when I started.

Having gone through the summer with the heat, when it was 85 outside it was about 90 inside the cave area. But this was without the ventilation system on. With the system on, it is constantly pushing the 77 degree air into the cave from below and it cools down nicely.

Step 9: Painting

Picture of Painting

I don't think I have ever been in a cave that has spray foam colored walls. So I needed to paint it.

I thought about what I wanted to paint it with, even researching the fire proof paints used for foam. The problem with that concept was this room is in the top of the house. Nothing above it would catch fire before something below it did. If the fire got through the floor and reached the foam, the smoke in the room would have already done the damage to anything living inside. So the high expense of coating the foam in the fire paint didn't make sense. As well, the rest of the foam in the rooms below were already covered with drywall. They would not be coated either, so risk analysis said don't buy the paint.

I instead chose to try and paint it with something that would be rubbery to protect the foam a bit. I made the wrong choice. I tried spray on bed liner, Rustoleum Leak Seal, and the rubber spray for under vehicles. The Bed liner spray and under vehicle spray both had a chemical in the propellant that caused the foam to weaken as it dried. The finish cracked funny. So those were a bust. I thought the leakseal was an option. I put 10 cans of it up on the ceiling as my test spot worked great.

First, I didn't do my job and read the ingredients. It contained toluene. In a small space even with the window open, the fumes were not good. This was the first time in my life that I screwed up with painting in a not well ventilated area. I had shut the vent fan off due to not wanting paint smell in the rest of the house with my wife being pregnant at the time.

Toluene is funny. You are perfectly fine for 5 minutes. then at 5 minutes and 1 second you get a head ache, and at 6 minutes it becomes harder to coordinate movements out of an area which I had to crawl out of. Toluene hits quick and shouldn't be messed with. Sadly I could have prevented it as I had the proper half face respirator with OV/HEPA cartridges. I just didn't use them. 5 hours of a head ache later, and feeling like I was going to throw up the whole time, I decided I wouldn't be so stupid on the paint again and used the respirator for the remaining 8 cans I had to spray. The 10 cans only completed about 1/2 of the ceiling. At 10 dollars a can I waited another month to buy some more.

I found though that after a few weeks, the foam started to weaken a bit just like with the other two products I tried. It didn't give me the rubbery feel I wanted at all, but was kind of crispy. I switched to just flat black latex paint and painted the whole thing with my Capspray HVLP spray gun instead.

So lessons learned. Don't spray toluene based things in a small space, and the 3 products listed above are not good to cover foam with, at least for the first layer.

Step 10: Flooring

Picture of Flooring

Who wants to lay on a hard plywood floor. That doesn't sound fun. But foam tiles on a floor. Now that is something I could crawl around on.

I purchased the 2 foot foam tiles with Microban technology to hopefully prevent the growth of anything on the foam. I know at some point there will be food left on the tiles or a cup of juice spilled.

The tiles interlock together and look and feel great. I used two colors, grey and green to give some contrast. The tiles are 1/2 inch thick so the floor is padded nicely.

Step 11: Finished Cave Pictures

Picture of Finished Cave Pictures

Here are a few pictures of the finished product. The cave came out great. It is a bit difficult for me to climb in and out of it but I am 29, not 5. Now I just have to wait a few years for my son to be old enough to go into it. He is currently 4 months old....  Until then, I might just have to go up there to escape every once and a while. Could be a good place to take a nap. Sadly, I can't hunt in my city even though I border a metro park. I saw two deer walking across the back yard yesterday while working in the cave area finishing things up. It would have been a beautiful shot through that nice window.

Hope you enjoy the room design and maybe you can build one yourself someday.


Crotus2k (author)2013-08-29

Fantastic. I new even before the last page that your son must be "new". I'd guess probably your first, as well. Congratulations. I can read the pride you have, every time you wrote "my son". I know exactly how that feels. Cool cave. Keep being a good dad.

Haunted Spider (author)Crotus2k2013-08-29

Indeed he is my First. His name is Asher. I almost made the green foam into an A on the floor but then decided if I had another child, they might not understand why they didn't get a letter in the cave. :)

JulsL (author)Haunted Spider2015-07-27

omg. My son's name is Asher. you don't hear that everyday! Hope he's loving his man cave

Haunted Spider (author)JulsL2015-07-27

It is a rather unique name. I like it a lot. Glad to hear someone else has an Asher out there. He actually doesn't know about the cave yet. It is a secret at the moment. I plan to show him when he is 3. Right now he is a bit over 2 and although he likes to climb on everything I want him to be a bit older before letting him play in there. Don't worry, he will spend hours in there shortly ;)

The Rambler (author)2013-08-30

Awesome project! I love how much planning and thought went into each aspect (i.e. insulation, ventilation, fire escape, etc.). As I was reading I suddenly thought, "But what if he leaves the lights on all the time?". Lo and behold the next paragraph down you had a plan covering just that situation.

I feel like a ladder or some kind of low structure to jump onto is a good idea for that 8' jump, but other than that I don't get all of the "Oh no, fire!" people. Houses are flammable, period. Matches aren't good for small kids to play with, period. This doesn't change if the foam is flammable. The wood it's attached to is flammable anyway. The important thing in any room of the house is having a good fire escape and being able to use it.

thunderchyld (author)2013-08-29

I love the project and the results, but as a foam installer, I do take issue with not covering the foam. Unless the foam company used Class A rated foam on install(doesn't appear so, Class A is almost always tinted for ease with the fire inspector) it's not up to fire code. The common requirement is for a 15 minute fire barrier. The best thing I could suggest is to add another layer of paint, making sure that it's an intumescent coating, like CP5901 INSL-X Fire Retardant Paint (INSL-X is a benjamin moore sub-brand).

Thank you for the suggestion on the paint. You are correct that in order for the code to be correct, I need an intumescent coating or even 1/2 inch drywall. But that is if I try sell the home and use the space as a selling point of usuable space. It doesn't meet the codes for a usable space in so many other ways as well, ceilings at 7 feet, HVAC run to the room, etc. It is covered by a barrier though when the little door is closed as the area below and walls surrounding have a coat of drywall. Also being a century home, the majority of the home is not up to code. With these in mind, and knowing the rest of the rafters are not coated either but connected to the crawl to the cave, I chose not to paint on the intumescent coating.

teenaginglikeaboss (author)2013-08-29

will you adopt me please ? very cool project

jpstockman81 (author)2017-07-19

You could make an epic Goonies lego diorama in there.

NetWt4Lbs (author)2015-11-17

Oh I love that you built this for your son before he was even crawling haha <3

EasyHomeConcepts (author)2014-08-23

This is too cool. Keep the kids jumping around in the attic and not on and off the sofas :)

AgnesMarin (author)2014-08-19

I love that! Once I've tried to make one of [url=]bunk
beds[/url]but I could do it. But I love your project and everything.

Tazmjm69 (author)2014-04-03

Great idea, you're a very cool dad!

Haunted Spider (author)Tazmjm692014-04-03

Thanks, I am trying to be a cool dad. Right now though, I am un cool if I walk out of the room to get something, or set my son down because I just can't hold him any longer. Ah, an 11 month old will do that to you :)

usMudack1998 (author)2013-10-22

Lol - "and Bandaids....."

:) a very important item to have on hand. I should have stock options in a company by now.....

blkhawk (author)2013-09-16

Fathers like you make the rest of us to look lazy and deadbeats! Congratulations on your project. :-)

Davesp (author)2013-09-14

Nice idea but as your adventures confirm this looks like a toxic play house. Apart from your comments about fire exits for your son I wonder what the foam will be giving off in the way of fumes?

I don't want to be negative, I liked the concept, when I looked at this it looked cool, I actually thought the ceiling was some kind of paper mache or recycled cardboard of some type and the floor was the paper packing you see sometimes in the bottom of fruit boxes, made from paper pulp.

Out of interest did you research any of these options?

Haunted Spider (author)Davesp2013-09-14

As I studied Chemistry of Hazardous Materials in College, am a safety manager in real life, and have done my research into all insulation options available, I am well versed in the dangers, options, and strategies in this build.

The foam will burn when heated hot enough, but with a torch it only smolders so the worry about my son lighting a match and causing a fire is minimal. In fact, all insulation burns at a certain temperature minus aircrete which can not be put in ceilings, and is basically talc powder when touched. If the home was to catch fire, the fumes from furniture burning, carpet below in the dining room, and paint that covers the walls in the rooms below would overcome any living thing prior to the foam ever catching fire, or even being kissed by the flames. You see, a fire code requires the foam to be covered if it is livable space. This space is not, it is a play fort plain and simple. The drywall on the ceiling below and the drywall on the outside of the closet for access do meet the code. The fire would have to break though both of these prior to getting to my son.

The insulation used is the best insulation for a home with limited space to install it. As the rafters are only 4 inches thick, it gives about an R 28 rating, where as dense packed cellulose would be much less. At the same point, dense packed cellulose has a fire inhibitor in it but it wears off after a few years as the chemical dissolves. When this happens you now have a flammable substance in your ceiling, and have you seen how messy that stuff is? Not the best stuff to breathe in for a play area.

The floor is foam squares like you would find in most playrooms and daycare centers. It is antimicrobial and designed for kids to play on, or for your feet in a kitchen if you have to stand for a long time. It also does not burn well but smolders. But underneath, it is backed by 1/2 inch plywood giving even a further barrier to flames.

I understand your concern but calling my playhouse toxic is not very nice and does not fit very well with the "be nice" policy. Since this foam is installed in homes across the country and in open attic spaces which many store things in and kids probably play hide and seek in, I imagine it is safer than you think.

I hope I answered your concerns and you can sleep better at night. I certainly sleep just fine and will be very comfortable with the risk I am putting my son in by allowing him to play in a space I designed to keep him safe, while building his imagination and mind.

bfk (author)2013-09-11

I too, would like to be adopted. Excellent project, and thank you for adding the escape window. Too many children are lost due to being trapped when the unthinkable happens. If the window isn't located over a porch roof or first floor entrance, you may want to plant some soft, low bushes under it (for safety & looks) and add a rope ladder your son could use to play "pirate" with as well as giving yourself a little peace of mind.

loafers (author)2013-09-08

This is amazing, you've done a bang up job mate!

Hiyadudez (author)2013-09-07

This is great! Awesome effect with the spray foam.

Could also be used as a p[anic room incase of some emergency :-P

Jetpack5 (author)2013-09-07

I had wanted to do this to my parent's crawl space when I was a kid. Thank you for showing me how cool it could have been! Well done and the best to your son!

shazni (author)2013-09-05

oh this is just perfect for a kid! it's a great hideaway place to dream and imagine all sort of play...just love it...hope you win :-D

Aaronius (author)2013-09-05

Fantastic! I appreciated the thoroughness on making sure he was safe, well ventilated, and had an escape route!

sabu.dawdy (author)2013-09-04

this is sooooooooo beautifulllllllllll

milesnorth (author)2013-09-02

Dang, I am entering something in this contest but I couldn't help voting for you anyway :-) Very NICE indeed! Lucky son!

wilgubeast (author)milesnorth2013-09-03

Awesome comment. This is what makes contests on Instructables so much fun: sportsmanship. Also: sweet forts.

I agree. Contests on here are fun and people are competitive but sportsman at the same time. Anytime I put an instructable in a contest, I always make sure to first not vote for mine, and second to vote for two others that I think are awesome as well. Good luck to all the entries.

angpal59 (author)2013-09-03

Makes you wish you were a kid again.

krimmy (author)2013-09-01

I really admire your dedication towards your family! Top stuff!

swim_guy5150 (author)2013-08-30

Jeez people calm down about fires he will be fine


Quester55 (author)2013-08-30

I didn't notice any mention of FIRE alarms, And you might Check into a Baby-Cam at amazon, they can be gotten cheap & come in Wireless or Wired, helps the NERVES(YOURS) If he gets too quiet .

Haunted Spider (author)Quester552013-08-30

A smoke alarm/ CO2 alarm will be installed on the back wall when he is old enough to play in there. As they have a limited lifespan on the sensors (CO2 being less than 5 years and still be effective), I am waiting to purchase and install. We do actually have a Baby Cam in his nursery at the moment. This will likely be moved into the room when he is a bit older.

Eric Sullivan (author)2013-08-30

I couldn't help notice that the ridge board seems to have been cut out inbetween all the rafters. Is something else doing that duty or is it normal in that type of contruction?

The Ridge beam or board never actually existed. I didn't cut it out. When it was built, they put a small wedge of board in where they met and then sheeted the top of with whatever they had. Some boards are 12 inches wide, some 16 and some 2. as it has stood over a hundred years, I didn't want to mess with the integrity and add in the beam and take a chance of shifting things. The foam should strengthen it a bit more as well.

Just wondered. i guess with all that boarding it would be pretty solid. Your son is very lucky I hope he enjoys it.

robdotrob (author)2013-08-30

This is so cool, Awesome job!

devineDIY (author)2013-08-29

How much did they charge to spray the insulation?

Zaqq (author)2013-08-29

This is an awesome idea. Does it have electrical outlets up there? I didn't see any in the picture and I was just wondering.

Haunted Spider (author)Zaqq2013-08-29

There is one outlet. The lights and fan plug into it. If they ever needed another plug, they could always use a grounded power strip. The wire feeding the outlet is 12-2 so it is plenty strong enough for a power strip with several things plugged in. I didn't want to have outlets though that were easily accessible for my son to stick things in.

zhamster rules (author)2013-08-29

Reminds me of batman! Go to the bat cave !!!!:p

HomeHaunter1 (author)2013-08-29

You are a great dad for taking this amount of time and effort exclusively for your kids enjoyment.

netkravler (author)2013-08-29

If you havent tested this allready. then take a piece of the foam and see if it will burn. Because if it can, your son dont stand a chance if it catch fire.

Even if this is a cool project and a great idea. It will never be aproved here. Not in the attich. Maybe some other place.

I stated earlier in a comment that I had tested the foam with a torch and it smolders, but does not burn. The hope is, if there is a fire and smoke starts to come through the fan, that my son opens the window, climbs out onto the roof and if he has to jumps 8 feet below to the ground to escape.

As far as being approved, to a building inspector, this is storage space in an attic. To me and my son, it is a play room as long as he wants it to be. But thank you for the concern and safety advice.

Please change your thinking to something more proactive. "The hope is..." should be "Our monthly fire drill plan is..." And how about an escape ladder for that last 8 feet. There are some from 30 to 40 dollars at Lowe's and Home Depot. The trick would be attaching it without a windowsill to hang it over. The escape plan and drill is not complete without having and reaching a designated Meeting Place, such as a tree or street light, a safe distance AWAY from the house. The fire drill will be fun, too!

Oh, my son will be sick of fire drills. As a safety manager, I designed and implemented an emergency action plan for my company. My son will have a plan tailored to him. The hoping statement is because he is 4 months old. Eventually, when he is old enough to be in there himself, we will have a plan of action. Part of his plan is learning to open the window, and lift it out of the track to gain full access to the roof. With a flat roof on the back of my home, I can put a very nice ladder in place for safety, and for me to get on my roof for putting up christmas lights.

DerekMc525 (author)2013-08-28

Awesome project, A+ Project and A++ DAD!

Glad you like the project. I hope my son isn't claustrophobic when he gets older. :)

About This Instructable




Bio: I work as a safety and health specialist for the NEORSD (Sewer district). I don't get to touch a tool on the job as ... More »
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