Shortly after moving into our 1929 home, we noticed a 2’ x 2’ access panel in a short wall in an upstairs dormer room.

Removing the panel exposed a small, slanted section under the dormer roof. There was room to crawl in, so we did.

What we didn’t expect was that after you crawled around the dormer roof, the space opened up behind the master bedroom wall such that we could actually stand upright.

We realized that we could put a hidden bookcase door in the master bedroom to access this area directly with no crawling around.

Haven’t done it yet, but it remains on the project list.

Old houses are fun!

Not a room but I found hidden secret drawers in my bedside tables after about 8 years of owning them. Then after about 12 years I found secret hidden drawers in the matching dresser!!

I found an abandoned root cellar in a house that I had owned for about a year or two.

I got curious when I noticed a large section of concrete on the back patio that the snow wouldn't stick to and it still took me forever to figure out it was because there was a void under it, making that section warmer than the rest of the concrete. Previous owners covered the entrance with drywall when they finished the basement and filled in the window well with dirt, so I thought it was just a planter.

My grandfather came to visit our new house and immediately clocked that the dimensions of the basement dont match the dimensions of the ground floor and he eventually found it. It was a fun afternoon with him that I'll never forget.

Mine wasnt a hidden room, but when I was changing my light fixture in my kitchen, I noticed that it was a drop ceiling and they had covered a whole set of upper cabinets. I removed the drop ceiling and now I utilize those cabinets. I still dont fully understand why they went with the drop and covered them... but now I have a lot more room to store stuff!

I discovered this only a couple of months after moving in.

I inherited a house from a retired cop and there was a hidden room behind a linen closet that backed up to a bedroom closet. It had 6 or 8 guns, a ton of ammo, tear gas grenades, and some other cool stuff.

It took seven years - no kidding!

We don't think the prior owners or the home inspector realized it, and it's not on the blueprints. Amazingly, the very old bulb still worked...

It's at the top of what we called our Winchester House "Stairs To Nowhere" in the basement - you couldn't see the door until you started to climb the stairs.

I haven't been in it. Only my darling husband was brave enough. It's at the end of a v dark narrow area of the basement, with so many spider webs that I'm convinced if I try to go in Shelob herself will eat me 🤣

Found a hidden closet. Previous owner put 12"x12" mirror panels over an entire wall. We were in the house less than 2 weeks before we got to that project. 3" purple and blue shag carpet was found. I kept that square of carpet for years....

I used to live in a VERY old house (like 1860s) and five years into living there I was scrubbing my kitchen floor because my roomate spilled something sugary like a bottle of syrup. On the floor of the kitchen pantry, I noticed when I dumped warm soapy water, it dissapeared really quickly, so after investigating a while, I found an area in the pantry floor the water was draining through cracks between the floorboards. I stuck a butter knife in the crack, and pried and a while section of the floor shifted. I put two screws in the floor and pulled and it was a secret door that lead to a full secret basement. I can't tell if it was a hidden room, or just a root cellar they stopped using and didn't mount a handle on the panel when they repainted. I was in college at the time, and we did some "gardening" in it for a while, but with a dirt floor and a 6 foot ceiling it wasn't the super coolest.

No hidden rooms but 2 secret compartments, and 2 secret access doors to access under the tub at the back of towel cabinets

My parents found a really skinny open space  behind one of the walls in their kitchen.  Now they basically just use it as a spice rack because it's only about a foot wide, 2 ft deep, and 5 ft tall.  We weren't really sure what the space was for, but we did find a petrified/mummified dead squirrel in there when we opened up that space.

Hidden attic space. Eight months in when I was building my rock climbing man cave.

I found a closed off room under the stairs in my 150 year old childhood home when I was a young. There was a large wooden grate for the furnace cold air return from which I could watch the living room without being seen. I kept this secret from my family for years.

I can't say that I've found one but I did recently renovate a friends home. I'm a GC and on his wish list was a few hidden areas within the walls so that he could store guns, ammo and personal items. I also renovated one of the baths and built a hidden room between a guest bath and master bedroom. He uses it for guns, ammo and a large safe. Pretty cool actually and hidden in plain sight

Not my house, but prior to marrying my sister, my BIL lived in a sharehouse that was formerly a coastal defence radar station during WWII (and subsequently a radio astronomy antenna facility).

One night, one of his housemates was off his tree on something, pulled up some floorboards in the kitchen, and found filled-in tunnels. I don’t think he got as far as breaking through the fill, but those cliffs were riddled with gun emplacements and subterranean passages.

My sister went to college in Thornton Heath, south of London, in the 80s. 4 girls shared the house and the landlord told them there was a locked cupboard. The 2nd day, they noticed a light on in the locked cupboard. They thought they could hear noises too, so knocked on the door. A man opened the door. Turns out he was a previous tenant on nights, about to move out! The locked cupboard was actually in his now unlocked room.

While in the attic of my first house I found a ladder nailed into a chase beside the chimney. It went all the way to the crawlspace and into a bricked up 4x8 room. There was a pack of Old Gold cigarettes and a jar of alcohol, I assume moonshine. Nothing else. I stored firearms there until moving out.

The previous owners of my childhood home put barn boards on the walls of the basement rec room. I was likely 8 when I found if you squeeze by the furnace in the furnace room, there was a small room behind the rec room. The barn boards didn’t go all the way to back wall, and left a 20x4 foot room. There was a small fireplace (right under the ugly massive fireplace upstairs,) and a couple empty beer bottles.

This is less exciting than most things in this sub, but there is a cupboard under my U-shaped stairs. There is a small bathroom on one side and an external wall on the other. I cut away a small section at the back of the cupboard to extend the cold water feed to an outside tap, and discovered a pretty useful ~1m² area. It isn’t a hidden room by any means but it’s useful for extra storage. I’d like to reapply the cupboard wall and make a hidden compartment once I’ve got something worth hiding.

Ugh now I'm on the hunt

In my dreams I have - so many times

Kind of. When I was around 8-10 I found out I could get behind the wall, under the roof, through a hole in the closet wall next to it. I had been living there since I was 2. My parents would have known about it but they didn’t tell me, I had to find it during hide and seek

I found a 2 foot by 4 foot space above a door leading into a stairwell when I was forced to renovate my kitchen due to water damage. I could not think of a clever use for it that made sense so I closed it back up again.

I remodeled our ground floor hall bathroom and discovered a small 2'x6' concrete blocked-in area underneath the toilet. It's as if they decided that the basement bathroom would look weird if that cutout wasn't removed, so they walled it in. It was filled with construction debris from the late '70s. Pretty lame.

Kinda felt that way the first time I saw how huge my attic is not gonna lie. I was like, “I could live up here” lol

I've been renovating one customer's home for the past 8 years. Different projects at different times. Started with the basement, then the upper levels including the washrooms. Followed by the laundry room and finally the main level including the kitchen, dining and family room. The last project is the powder room which is half a flight of stairs down. I realized that based on the layout that the ceiling could be raised from 8 feet to 12 feet. I plan on doing a vaulted ceiling treatment with a long chandelier to add some drama to the space.

When our neighbour died, my father bought his house to remove it to build parking spaces. It was our second or third visit inside, there was a complete mess of garbage, tools, ancient furniture, when we saw that drywall on the second floor that didnt match with the wallpaper. Also the whole space didnt match with the rooms on the ground floor. We teared down the wall and behind was, creepy as hell, a childrens room with race cars on the wallpaper. We later found out the neighbour had a son who moved out with his mother after she filed for divorce.

It was a relief when the whole place was teared off a few weeks later.