Advice on the restoration of an old country house

[helenxmas]

I'm writing a novel, a large part of which is centred around the restoration of an old country house (c. late 1700s). I've already done a fair amount of research, but there are still a few topics I am a little unsure about and over the next few weeks would like to post a few questions on this forum for discussion.

One scenario is that, the house has suffered damage from woodworm and damp. I live in an old property myself where there are visible signs of woodworm, but you can only see this in the exposed beams. I understand that the embedded timbers in an old property can also be affected and due to the damage caused by death watch beetle, some timber replacement is often required. But how is it possible to diagnose how deep the damage lies?

Has anyone had first hand experience of this? If so, can you explain the technique used by a surveyor (or damp specialist) to find out whether or not the embedded timbers in an old house are suffering from either of these problems.

 

[Penners]

I'm writing a novel, a large part of which is centred around the restoration of an old country house (c. late 1700s). I've already done a fair amount of research, but there are still a few topics I am a little unsure about and over the next few weeks would like to post a few questions on this forum for discussion.

One scenario is that, the house has suffered damage from woodworm and damp. I live in an old property myself where there are visible signs of woodworm, but you can only see this in the exposed beams. I understand that the embedded timbers in an old property can also be affected and due to the damage caused by death watch beetle, some timber replacement is often required. But how is it possible to diagnose how deep the damage lies?

Has anyone had first hand experience of this? If so, can you explain the technique used by a surveyor (or damp specialist) to find out whether or not the embedded timbers in an old house are suffering from either of these problems.

If timbers are badly affected by infestation, the visible ones will show all of the obvious signs. If those signs are apparent in the visible timbers, then it's a foolish person who won't infer that the unseen timbers are also affected.

But ultimately, the only way to see how bad the infestation is would be to start digging into the wood with pointed instrument. Badly affected timber will be soft and crumbly. This is not, of course, a precise metric, but it gives a pretty fair idea of the state and depth of the infestation. If it seems bad and deep, then you can start raking off the soft, crumbly material and keep doing this until you hit sound wood (if you do!).

 

[DJH]

The simple way of course would be to drive an awl or pointed nail into the timber and how far it penetrates will give an indication of how deep the rot is.

Look forward to reading your novel. Does a 'damp expert' meet a grisly end by any chance ? :lol:

Doug

 

[MatthewC]

Be aware that woodworm does not survive if the wood is dry enough (I think <14%), so the presence of woodworm exit holes does NOT infer that woodworm is still present. Also, it is often surprising how little of a beam has been affected - they like the softer wood and so may only infest a small part of the cross-section. If the beetle (it's not a worm) is active then a light dust can be seen where it falls from a rafter or purlin.

What sort of end should we suggest for a "damp expert"? Chinese water torture followed by embalming?

 

[worms]

...can you explain the technique used by a surveyor (or damp specialist) to find out whether or not the embedded timbers in an old house are suffering from either of these problems.

The answer to your specific question is that the average surveyor/damp "specialist" uses a mix of types of witchcraft and augury so that he can sell his particular brand of snake oil as the panacea for all ills. The heros of your story will undoubtedly expend vast sums of money on wasted treatments before turning to PPUK for advice and living happily ever after.

 

[Matt Green]

those of us that put more faith in science than witchcraft when we were looking for embedded beams hollowed out by death watch beetle used a wood decay micro drill like the DDD200 by Sibtec:

http://www.sibtec.com/digitalmicroprobe.html
http://www.sibtec.com/howitworks.html
http://www.sibtec.com/applications.html action shot

The IML Resistograph is a similar device:
http://www.imlusa.com/shop/test-and...ies-for-tree-inspection/iml-resi-f-serie.html

The idea is that you apply constant pressure to the drill and a resistance trace is generated as the very fine bit moves through the timber. If the bearing is hollow there is no resistance to the drill bit and a co-responding gap in the trace output. More here (but is is not well formatted and makes little attempt to engage non-specialists): http://inspectapedia.com/structure/Micro_Drilling_Wood_Test.php

As for water deep within the fabric of the building, a thermal imaging camera is a good bit of kit to find cold spots brought about by water penetration. Alternatively:
-drill a core from the wall (hammer drill)
-collect it (zip lock bag)
-weigh it
-oven dry it
-weigh it again
= moisture content at that point (height and depth)

repeat steps to get a profile across the walls and building. Leave the cores over salt solutions and re-weigh to get an indication of the amount of dissolved ground salts in the core samples- that tells you if the water is ground water or rain water.

I miss the old days. Sometimes. Not when it's raining.


Matt

 

[helenxmas]

First of all, thanks to all of you for your advice.

The roof timbers were badly affected in this story and I certainly imagined that the wood would turn soft and crumbly. There is also a scenario where book case is visibly affected and this is the point at which the property expert is advised that "Death Watch beetle prefer damp conditions. The damage caused is extensive, because they tunnel right through to the centre of the wood. Without treatment, this could eventually render a property structurally unsound."

I hate to disappoint anyone, but no damp expert meets a grisly end in this book. It is more to do with an unscrupulous property developer who wants to get his hands on a fictitious listed property in order to turn it into an exclusive Hotel and Country Club for the corporate sector. James, the property owner, is bound by tradition and resistant to change - fearing this man's ambition will ruin the character of his beautiful ancestral home.

But it through a process of manipulation and deceit, that this man tries to get James to give up his property. First via a survey which lists extensive damage (damp, dry rot and death watch beetle infestation) to the inner core of the property. It is recommended “that the only cure, would be to cut out the affected timbers and have new ones spliced in - work which was labour intensive and due to the decorative nature of the building, exceedingly expensive!”

However, James finds himself a property expert who doubts the accuracy of the survey and thus “calls in a firm of damp experts” to assess whether this is true - which it isn’t! They eventually expose the survey to be a scam - part of a long term ploy to scaremonger James into accepting a deal i.e. letting the unscrupulous property developer take over the house (which is the part of the story I am working on now).

So the property owner probably would have wasted money if he hadn’t finally been given the correct advice!

When I get a moment to study all the advice, I will make mention of some of the techniques described - especially from the very detailed reply from Matt! Just one last thing I should say, this story is set in 1986 (would thermal imaging cameras have been around then?) but the fine boring instruments can certainly be included.

I’ll no doubt be coming back for some more advice shortly. But thanks again to everyone who took the time and trouble to reply.