I have a mid-60s house in the UK, at the front of the property at spanning DPC level there's a small metal cover (approx. dimensions are 1 brick wide and two bricks tall). None of the neighbours seem to know what it is for, and I can't remove it to see what it is covering.

Does anyone know what it might be from your previous experience. All the houses have it. All the houses had traditional flue chimneys that could take a coal fire, so maybe it's something to do with that, but I am not sure. Its on the outside wall of the front room that contained the fireplace (chimney and fireplace are long since removed; there were no signs of a channel going in that direction when it was removed)

There are no markings on it, it feels like it might be iron, I can't see any fixings, and it doesn't budge (by hand - I am nervous of encouraging it with something heavier until I know what it might be).

The floors inside are poured concrete, so I don't think it's an airway; there're no other air bricks or anything like that on the property

Edit for additional clarity: The house is link detached, where the garage of one house shares the ground floor wall of the next house, and so on. The item pictured is not attached to the same wall as where the chimney and fireplace were, and is positioned underneath a window around 3 meters diagonally away on an adjacent wall. The fireplace was on the same wall that joined the neighbours garage. This is on the front wall of the house, with nothing on the opposing wall of the house (some suggestions it may be a tie plate, but I don't think its one of those)

Appreciate any wisdom you might be able to throw at it!

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  • 7
    I'm thinking some sort of clean-out for the long-gone fireplace. But it's just a wild guess.
    – brhans
    Commented Oct 19, 2023 at 11:55
  • 1
    Some old homes in the US had doors similar that opened to coal chutes. Allowed coal to be delivered into basements for furnaces.
    – RMDman
    Commented Oct 19, 2023 at 11:56
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    @RMDman - a coal chute would be bigger - something a shovel would fit into. Fireplace ash cleanout (outside so you don't make a mess) is much likelier.
    – Jon Custer
    Commented Oct 19, 2023 at 12:38
  • 1
    @Max edit that info into your question, don't bury it in the comments.
    – FreeMan
    Commented Oct 19, 2023 at 13:54
  • 1
    Have you asked your local planning/building guys? If anyone would know, it's them.
    – Tim
    Commented Oct 19, 2023 at 14:03

3 Answers 3


I'm with brhans - I think it was a clean out for the fireplace. We had something very similar on the house I grew up in (USA) on the wall outside the fireplace.

You might want to contact the local historical society to see if they've got any documentation on the houses when they were built new. They might even have floor plans which would show that this was the location of the fireplace. If the houses in your neighborhood are all the same, they might even have the architectural drawings that were used for construction that would confirm exactly what it was for.

  • Thank you for the suggestion. As you may see from the comment I placed on the post below, I wasn't clear enough with my description and photo - sorry. The cover is on an adjacent wall, under a window, from where the fireplace once stood Sadly I've not been able to find anyone who has any drawings retained from the period it was built, and as yet nobody has done any remodelling work that might have helped to uncover it's purpose.
    – Max
    Commented Oct 19, 2023 at 13:17
  • Also, the wall where the chinney was is joined onto the neighbouring properties garage wall, I wondered maybe in the past whether it used to be an airway to feed the fireplace, and was modified to block it off, but it's odd (to me) that all the houses have it - many still have the fireplaces, so I discounted that idea
    – Max
    Commented Oct 19, 2023 at 13:20
  • @Max you still may want to contact the local historical society to see if they have any information about the original construction of your neighborhood. They may be able to tell you right off the bat, or at least be able to start you down the right trail to figure it out.
    – FreeMan
    Commented Nov 28, 2023 at 13:36

A solid-fuel fire needs a fresh air supply, because the flow up through the chimney needs a compensating inlet. This blocks off what would originally have been a grating (which might still be behind it). Without the inlet, there would have been a draught, probably around the door from the hall into this room.

This should have led under the floor, with smaller gratings in the floor on each side of the hearth, so the cold air from outside does not go through the main part of the room.

  • 1
    Sounds good but I have never seen such a thing. Can you provide any references, pictures or links to a system like this? Also, OP says he has a slab floor and his mystery thing is above grade, so unlikely to be a sub-floor airway.
    – jay613
    Commented Oct 20, 2023 at 13:14
  • I find this a reasonable explanation given the closeness to fireplace. I had a house here in Chicago built in the 60s where the older furnace was about 10 feet from the outlet for the dryer. I crafted a cover to prevent the outlet during the winter from allowing the cold air to just flow into the room, but I found that the furnace relied on it during operation to feed combustion and with the cover, I started to get air and odor drawn up from the crawlspace. I played with that for awhile before I discovered they had butterfly valves that opened themselves when air was to be pushed or pulled.
    – J D
    Commented Oct 20, 2023 at 16:19
  • I can see on an old house someone having a mechanism to open up an inlet and a flue, and then closing them when the chimney wasn't in use.
    – J D
    Commented Oct 20, 2023 at 16:21
  • @jay613 Not seen one since I stopped installing central heating. I found a site that sells Black Ornate Cast Iron Air Brick 9.25" x 6.5" which seems about the right dimensions compared to the bricks. It may be a bit shallow, and has a thick fillet of mortar at the bottom, so this may just be a "close enough" oddment cemented in (possibly not very securely). Commented Oct 20, 2023 at 22:06
  • @jay613 I am doubtful about the floor level. I think I see a Damp Proof Course and a double layer of mortar above the first complete brick layer, and the floor should be above that. The vent would be just a gap in the bricks and could angle downwards in the thickness of the wall (which should be double brick with an air gap, total about 13 inches). Commented Oct 20, 2023 at 22:08

Could easily be wrong, but it looks like a welded tie plate to me.

So the flat bar in the middle would run through the building and there would typically be a matching plate on the other side of the building. Old ones tend to be fancy nuts on threaded rods. This looks like you'd have a plate with a hole for the bar in it, and your welder comes along and welds the bar in place, then your painter paints it.

  • After reading this I no longer see a door. But IDK, would a 1960s brick house be designed with exactly one tie plate, so large, so exposed and so close to the ground?
    – jay613
    Commented Oct 19, 2023 at 14:45
  • I would guess with "one per house" and the wall joined to the next house wall and the UK, we're perhaps looking at row houses, so there would be multiple per structure, where a structure has many houses along its length. Mostly I'm just going on what I see in the picture, without discerning the designer's intent as we don't have an overall idea of how these fit in.
    – Ecnerwal
    Commented Oct 19, 2023 at 15:10
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    It does look a bit like a tie plate - but why would one be so close to the ground, when it would be far more use up at attic-height? Hmm… does the area have known subsidence? Old mining area perhaps? There is a small fault line we can see in the brickwork.
    – Tetsujin
    Commented Oct 19, 2023 at 16:03
  • It does seem a little low for a tie plate, and there is no similar (nothing in fact) on the opposite side of the house. It would explain why it won't budge though!
    – Max
    Commented Oct 19, 2023 at 16:30

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