My Extension Isn't Attached to the House!

[JohnB]

It's been years since I was last here, so I'm glad to find you're still around!

I've just discovered that my 1960s brick kitchen extension doesn't seem to be attached to my 1850s stone house. The crack in the render is wider as it goes up, but I just knocked this bit off that I could reach from the ground. What can be done to fix it? I'm hoping to have the house externally insulated and rendered* very soon, so need to do something quickly. There's also a narrow crack in the corner inside. I suppose there could be something holding the walls together, but the owner who did this was a master at dodgy building work, so I have my doubts!



*Breathable insulation and lime render, so don't panic!

 

[Feltwell]

Helibars is my first thought - a popular way to repair masonry cracks, you could use them to tie in where a joint aligns

 

[Abi Cott]

Helibars is the plan for the rear wall of my house (LBC pending). My 1829 rear wall is not tied into my 1829 party walls. Apparently built that way from new, and it seems to have stood up pretty well so far.

However my 1829 rear wall is also bowing in one of the skins and that gives structural engineers and mortgage companies the collywobbles so something needs doing.

Helibars appear to be the least intrusive available option.

 

[JohnB]

Helibars seem like a good idea. They look straightforward to fit. A quick search came up with a complete kit with 10 bars from Screwfix for £200. As I hope this would be a one-off job, would a builder who might be doing other jobs for me have the kit already, and be easier and more cost effective than doing it myself?

There's also the join at the other end to consider, that's half way along the house, so making a T connection with the original wall, and what I think is an early 1900s filling in of a doorway on the first floor that hasn't been keyed in that may need doing.

I need to talk to the insulation installers about this, to see what they think, and if they'll do it, maybe as part of the job. It's being done under the Energy Company Obligation scheme, so is costing me my favourite price - nothing. Except for any extras that I need to keep to a minimum.

 

[Abi Cott]

I'm aiming for two bars spanning the rear face of the terrace. Tied into four bars set into the internal party walls.

I don't pretend to be an expert but their description of resins holding the bars in place within the stone work suggests your t situation might be fairly simple. Depending on the thickness of the original wall.

 

[JohnB]

The original house has 600mm walls, with earth mortar, and the extension is brick cavity. Although that corner has a much thicker wall on the end, where it's flush with the front of the fireplace, so I'm not sure how thick it is. I think the next step is to see what the insulation installation company says, as they do all types of building work too apparently. I'm too busy digging away the concrete and soil from the base of the walls, so I can get the ground level below floor level, while I've got the chance!

On the subject of unattached walls, today I found the remains of what passed for the foundations of a former stone lean-to on the other end of the house. There's not the slightest sign that it was ever keyed into the main wall!

 

[Abi Cott]

I'm an archaeologist by training. Lack of tie in is generally just considered a stratigraphic indication in archaeological terms.

 

[88v8]

I'm an archaeologist by training. Lack of tie in is generally just considered a stratigraphic indication in archaeological terms.

I'll bet it was pretty common.

One end of our c17 stone cottage isn't tied to the other, and in early c19 chimney stacks were built at each end, which also aren't tied in.
And the front of the cottage where I'm sitting, or am I supposed to say sat :roll: I recently realised was once part of another cottage that was grafted on with no tie-in other than some rather botched connections in the timber frame.
Are there cracks? Yes. Maintenance.

Resin bars will stop differential thermal movement. but the extension is sinking relative to the house, and if it continues sinking then eventually it will crack again, just differently. Of course, 'eventually' is a flexible concept.

Ivor

 

[JohnB]

Resin bars will stop differential thermal movement. but the extension is sinking relative to the house, and if it continues sinking then eventually it will crack again, just differently. Of course, 'eventually' is a flexible concept.

That's a good point, as the foundations for the two parts of the building are very different, I assume! This is the other end of the original building, that I uncovered yesterday, and I can't imagine the same technique would have been used in the late 1960s, even by the then owner, who seemed to delight in bodged jobs!

 

[skier-hughes]

My extension isn't tied in and it was built about 50 years after the main house, so about 1580