Fircroft Chronicles

[Cubist]

As rain has stopped play, hopefully only temporarily, I decided that now would be my best opportunity to provide an update on progress with the Infill Panel Caulking project I discussed in my introductory post. As a quick reminder; the First Lady and I are the bonkers stewards of 16th Century Oak Timber Frame cottage on the Shropshire / Herefordshire border which was fully restored - from the ground up - about thirty years ago. Since then the new timbers that were introduced have naturally shrunk and gaps of up to 10mm have opened up in may places. Previous owners, I'm sure based on best advice available at the time, tried to remedy this problem using silicon sealants and other now inappropriate materials. When this remedial work was done the timber shrinkage process was not complete and consequently these materials have either parted company with the timber frame and/or the infill panels - fortunately.

In my first post I was looking for some guidance concerning my thoughts on the most effective strategy to correct this problem, and in light of the fact that during the restoration of the building a portland cement based render had been used for the infill panels. I will not bore you by recounting the options I was weighing at the time, and the valuable advice received from contributors to this forum, except to say that my chosen strategy was to remove the inappropriate silicon sealants, where necessary open an air gap between the cement render and the frame, pack the resulting cavity with Oakum and/or Caulking Cotton - thus isolating the cement render from the timber - but leaving a cavity of 15-20mm deep that could then be filled with Lime Putty to close the gaps permanently.

That was a couple of weeks back now and after a few false starts, owing to failures to get the desired finish with the lime putty and the need to experiment with different grades of sand and ratios of putty to sand to produce a suitable and effective final filler I now feel that I making some serious headway. That said however, with all the other not to be neglected tasks around here, I suspect that much of the summer and early autumn will be needed to finish the job - hopefully.

On balance I am very pleased with the results and frankly I am very impressed with the versatility and performance of Lime in all its forms - though why that should be new to me given my lifelong admiration of the Pantheon I know not. True, it can be difficult to work with but seemingly it is also quite forgiving provided you get the mix ratios right. Given the weather over the last weeks and the fact that I've been forcing the lime plaster into crevices some minor cracks did appear but diligent misting and brushing overcame most of these. Inevitably there a few spots where I had to root out some of the plaster and refill to get a structurally sound finish but the lime whitewash I was using, applied sparingly and frequently, filled any remaining minor fissures.

During the course of the work so far I have been pleasantly surprised by some unexpected events and circumstances. Initially I was informed by one Lime products supplier that Lime mortars would not bond with cement based renders this does not appear to be true. Good, clean and sound bonds appear to have been achieved in most of my efforts but that may be due to the fact that I am forcing the material into relatively small but deep crevices between the original mortar render and the timber frame.

In addition I have found little evidence of damage to the timbers owing to the use of non-breathable products - probably due to the failed silicon treatments allowing air to circulate and perhaps aided by the near 50cm thatch overhang helping to keep rain water off the walls. So far, so good but I suspect I'll be having some unhappy moments as I progress around the remaining 80 infill panels.

I am still struggling to get photographs embedded in these posts but will continue trying as requested by some in reply to my earlier post. I have also decided that this forum would be a good place to record some of the past and future repairs and enhancements we have made to the house - hence the subject header 'Fircoft Chronicles'.

I'll keep you posted and will shout for help, commiseration, et all as circumstance dictates.

Cheers,

Cubist

 

[plasticpigeon]

I'm glad its going well. I tried to bed a synthetic cement stone window sill in lime and it didn't stick at all. I redid it in 1:1:6 mortar and it stuck ok. I also wonder if burnt sand mastik might be useful for some of your cracks, just in case the lime doesn't work in some circumstances.

 

[Cubist]

Thanks Plasticpigeon,

Yeah, I think the interaction between the aggregate and the lime putty - if properly blended - produces a much more powerful bond than pure lime putty somehow. I'll check out the science behind that sometime. Clearly I should have paid more attention to that aspect when I was watching a tv programme (Underground Rome?) which discussed the use of Porcelanosa mined from under the city to create the concrete used for the dome of the Pantheon. I should also check out why it gets stronger over time - probably continued carbonisation but I'll satisfy my new curiosity anyway - hopefully what I'm doing will last as long. Go figure; modern concretes - 25 year life expectancy, Lime Based Concrete 2000 plus years!

Thanks for the idea regarding burnt sand mastic. That appears to be what the carpenters used to seal or close some of the timber joints during the original restoration work. Sadly, in some instances, I have had to dig this out too as either they did not fully fill the gaps or shrinkage has opened them up and caused some cracking to its surface that has allowed water ingress. It's interesting stuff when dried as it looks, feels and behaves like a fine clay mixed with a hard wax (rather like a crayon in fact) but my guess is that you have to wait a few years after first application to get a 'tidy' finish - most of the stuff on the house looks like a stormy day at sea. No criticism of the carpenters intended, my shaky hands would probably look like something produced by a hurricane. I think I'll save this option for the bits no one else will ever see until I'm long gone.

Will try to get some photos uploaded, as promised, and may include some before/after stuff if I remember to take the camera out.

Cheers,

Cubist

 

[Cubist]

Finally, I think I've got this photo posting sorted out. I appreciate that this forum is dedicated to 'Older Properties of Character' but really, must that include archaic web-site technology?

Anyway here are the promised pictures of the house with a few comments thrown in where relevant.

This one was taken while we were negotiating to buy the place - the gruesome green paint managed to survive until the following spring when it was replaced, on the demand of the First Lady and as a part of her efforts (continuing) to acquire a controlling interest in Farrow and Ball.

Apologies for the 'fish-eye view' but this one provides a more accurate view of the place today.

Winters can be tough out here in the sticks.

And can make walking around the place a little dangerous.

But some of the neighbours are friendly - the First Lady calls this one 'Kevin' but he, like all his kin and the other 'lodgers' we get, refuse to pay rent.

I hope these are of interest and I'll post more from time to time provided I don't forget how to do it.

 

[Cubist]

The trouble with starting a new project around here, and I'm sure that other members of this forum will have had the same experience, is that as you progress you come across one or two other things that need to be done - some sooner than others.

I was working on the gable at the western end of the house today to complete any caulking of the infill panels that may be necessary whilst also attacking some of the induced extra work of re-painting (white-wash) of the panels after repairs and oiling the timbers. Only to be presented with two more jobs for my list. The first concerns the discovery of a rotten gable fascia board that must now be replaced and the second being the discovery of yet more silicone - huge lumps of the stuff - used to repair sections of Burnt Sand Mastic which had perished.

Ho hum, and its off to more work I go with visits to Ty Mawr in Brecon and my local Travis Perkins for the necessary bits - postage charges from Ty Mawr outweigh the trip cost.

 

[plasticpigeon]

Very picturesque! Looks like you have a property worthy of all the work.

 

[Cubist]

As rain has stopped play yet again I have an opportunity to grumble at one of the previous owners or perhaps one of their tradesmen.

Whilst prepping the eastern end of the house, which has helped me avoid some of the stronger afternoon sunshine, I discovered that some clot had decided to use putty to fill some of the gaps that had opened between the infill panels and the timbers. Unfortunately this was of the Plumbers variety, typically used for sanitary-ware, which does not set! Getting this out has proved a bit of a nightmare because I felt the if I left any scraps of it in situ the likelihood of a good bond for the Lime render/filler would be minimal. So lots of cutting and scraping later and after amassing significant amounts of this horrible sticky stuff - mostly to the soles of my boots - I felt that I had made some progress until the First Lady posted out that my vigorous efforts had also produced numerous, but individually small, holes and breaks in the internal plaster.

Ho hum, and its off to more work I go.

 

[MatthewC]

...I discovered that some clot had decided to use putty to fill some of the gaps that had opened between the infill panels and the timbers. Unfortunately this was of the Plumbers variety, typically used for sanitary-ware, which does not set!

Perhaps they thought that they were being clever by allowing for movement? 8)

Matthew

 

[Cubist]

Perhaps they thought that they were being clever by allowing for movement? 8)/quote]

I suspect thats true and quite smart but as its 'non-breathable' its just not appropriate - not least because of the amount of time it took me to get it off the sole of my boots.

 

[88v8]

...but as its 'non-breathable' its just not appropriate ....

<thinking aloud> No, but.... if it's overpaintable.....
After all, there is the whole surface area of the adjacent panel to 'breathe'. If we think of a stone wall, the stone is non-breathable, it breathes almost entirely through the lime pointing which constitutes a fraction of the total surface. Not every element of a breathable structure needs to breathe.</thinking aloud>

There is that fundamental mismatch in half-timber construction between the frame which swells and shrinks with the seasons, and the infill panel which doesn't. Look at any half-timbered house whch has been left to its own devices for a few years and one will see varying degrees of incipient dereliction.
Often, we aggravate the tendency for movement by following that Victorian habit of blacking the wood, and whiting the infill, thus exacerbating the movement through differential thermal gain. Far better to limewash the whole thing including the wood. But black n' white does look good.
Here, there is some perimeter cracking, and rather than adding more of the limestuff or daub that's already failed, in places I will be using some sort of flexible caulk.
And yes, I should have done it while the weather was good. Fortunately our relatively small half-timbered wing, nothing that compares to your lovely example, is to the north and gets little weather, otherwise I think it would have rotted away long ago.

One of the most flexible and paintable caulks is Decorators filler, usable outdoors it says although I wonder about its durability, then there are various levels of builders' glops, and marine sealants.

There are limits. If the gap is overly large, then some lime to reduce the gap, followed by the flexible stuff?
And how to de-dust the joint?
And how to prime it? Can't, really, which somewhat dooms the process.

And it's a good point, the problem of getting it out again if the joint fails once more.

Dunno, but it does seem rather futile to repeat what didn't work the first time.

Ivor

 

[malcolm]

Well worth a look at Pete Ward's timber frame inspections on Youtube before you use caulk Ivor. He's forever pulling flexible caulking from ancient timbers that were OK until the invention of flexible sealants. The wood needs to breathe to the render and any waterproof barrier will end up with water against it causing rot.

 

[Cubist]

Well worth a look at Pete Ward's timber frame inspections on Youtube before you use caulk Ivor. He's forever pulling flexible caulking from ancient timbers that were OK until the invention of flexible sealants. The wood needs to breathe to the render and any waterproof barrier will end up with water against it causing rot.

Thats the beggar that gave me nightmares in the first place - just wish he would discuss solutions as well as grumbling.