Un-keyed Victorian extension butting to Georgian structure

[michael]

I saw your response Gervasse to Geoffs topic “New Walls butting to old” and wondered if you or any other building engineers out there might be able to advise me on this.

My old Baptist chapel home built around 1817 is a two story gable fronted building of nine inch solid brick construction comprising of an open plan ground floor with first floor balconies on three sides complete with box pews.

Recent exploratory work involving the careful removal of some original T&G timber wall panels at balcony level leads me to believe that the gable end frontage and entrance is a Victorian extension. This frontage which has a stucco façade based on classical designs of imitation stone blockwork and arches extends into the original chapel by about six or seven feet creating and entrance lobby and an enlarged balcony above.

My concern is that this extension does not appear to be keyed into the original building, in other words the new Victorian brickwork appears to finish flush against the original Georgian brickwork with an obvious vertical un-keyed join straight up through the building (at least as far as I can see with the panels removed).

The original building has been standing for at least 190 years and I estimate that the Victorian addition is about 130 years old. From the outside the building looks decievingly like one structure with the victorian structure having its original render extending around the sides of the building to cover the join. There is also a common and unbroken roof covering the two stuctures with matching internal rafters and wood plank ceiling.

There is no evidence of any structural defect other than an area of about 2 or 3 feet square on the Georgian side of the “join” on both sides of the chapel at balcony level, where a good few stretcher bricks are missing (hidden for 130 years behind the panelling recently removed) and presumably left out by the original builders. I intend to replace these missing bricks but should I consider keying in the replacement stretcher bricks between the Georgian and Victorian structures and should I be concerned about the majority of remaining original un-keyed structures.

 

[Gervase]

I'm afraid I ain't a building engineer - just someone who works on old houses. No fancy letters or qualifications, just grubby hands!
However, on the basis of what you describe, I wouldn't worry about the chapel extension. For it to have stood for 130 years without any drift or cracking in the render is testament to the skills of the Victorian builders, and I would suggest that any modern work to 'tie' the two parts together would be as likely to cause movement to start as to prevent it, unless you are talking about hugely expensive helical steelwork and the like.
I'm a great believe in the "if it ain't broke.." principle, and this would appear to be a perfect application for that.
In your shoes, my only cause for concern would be if what appears to be the first signs of global warming does prove to be the start of something more drastic and your subsoil dries dramatically over the next few years.
Even then, though, that might not cause problems with the building. The Victorians could and did use some hefty concrete foundations, and chapels and other public buildings were often built to a far higher standard that ordinary domestic units, which were sometimes very shoddy indeed.

 

[Lime]

As Gervase says it has stood for 130 years and hasn't moved, so why touch it now?

The area you describe as

on the Georgian side of the “join” on both sides of the chapel at balcony level

could have had something else attached in the past.


I'd leave it alone.

 

[Penners]

I'm afraid I ain't a building engineer - just someone who works on old houses. No fancy letters or qualifications, just grubby hands!

Oh, go on! Comb your hair, put on a tie and clip a biro in your top pocket. Feel posh - at least for a day or two!

There is no evidence of any structural defect

As Gervase and Lime have both said, if you're dead set on finding something to worry about, this doesn't like a good candidate. :wink:

 

[sarahj]

Our whole 2 storey house is butted onto a 3 storey house with only the door lintel keyed in! However,it has been there since 1837 and then in 1868 the house next door put the third storey on and I think caused a bit of movement to our house, but we are stone built on stone so I think the house will stand for ever.

 

[Anys]

Don't be too sure things won't go wrong - when we bought our 17th century farmhouse 20 years ago the outside chimney on the gable end was letting in rainwater into the inglenook (it still does, but that's another story.) So renovation started and the builders were repointing the exterior of the chimney (which sticks up outside the house like a thumb), there was a rumbling of stones, the builders jumped clear in time and the whole chimney fell down. There had been storms beforehand and so luckily insurance paid for the chimney to be rebuilt. We found out it had never been tied in to the main house, just bodged through the centuries. This time we made sure the chimney was tied in, 'well fettled' as they say round here.

 

[Moo]

It's not so much a question of whether tying-in is essential - more of how well the addition is built in the first place.

Our house-before-last was built in about 1812 and then doubled in size about five years later. Nothing was keyed in, but 150 years on the courses of bricks were still parallel and there was no sign of a crack anywhere (except, of course, for the victorian bay that had been tacked on to one room).

 

[Lime]

As an addition to my post above and

My concern is that this extension does not appear to be keyed into the original building

I wonder what key there is that cannot be seen.
Many victorian added bits were held by iron inserts within the brickwork.