How to treat really old beams?

And as I've said many times, the damage waterproof rendering causes is now known. Thats basically the definiton of 'wrong'. Whats news here? If you have a proposed method you think prevents the damage it causes, either to brickwork, stone or timber frame, I'm all ears. I've a feeling you don't though.

really, no. Attempts to control damp that cause expensive damage to the fabric of a building are all too familiar.

Another popular myth. Damp doesn't 'get in', the net flow of damp in all houses is from interior to exterior. Think about it: we cook, we breathe, we shower; if the net flow of damp werent from interior to exterior the house would flood.

Assuming the house is maintained and water isn't pouring in somewhere, then problems result when the outflow of damp is insufficient.

Why don't you go find out how it damages buildings.

of course. Houses that do move do need soft mortar. People do sometimes spend unreasonable amounts of money on underpinning without good cause.

yes quite - I wish today's BR took that and more into account. Its not so hard to do either.

Why houses are gone is another topic, mainly down to higher density redevelopment as population has increased. A house has to be in a hell of a state before rebuild is cheaper than repair.

They are mostly in a bad way with damp because inappropriate repairs and maintenance approaches have been used. The idea that century old buildings were faultily designed is just a persistent myth. Faulty designs are rare.

quite. Several times as long.

Really no. Look in any estate agent's window.

I dont think barn conversions tell us much about the ability of old houses to meet modern needs. They're old barns, not old houses.

yup :)

There are rather more sensible methods than that. You propose a straw man there.

Just insulation and draughtproofing works pretty well. If you want to take it further HRV is far from expensive.

I'm unclear if youre describing interior, exterior or cavity insulation. All 3 work fine on old houses, if done right. The large number of all 3 in satisfactory use demonstrates that.

There is just no basis for such a claim. Obviously at some point they got heating and electricity, just as a new build does on day 1.

I've seen quite a lot of old houses, and very rarely do they need redesign. I don't know why you think they do.

Are you going to claim all old construction is like that? Every era has its failed bodges, the old ones are usually long gone. That's one of the plusses of old properties: regardless of modern build regs, a century or more has proved their ability to work satisfactorily in almost all cases. The level of complete failures on modern properties will likely be higher than on the remaining stock of century old builds.

... all of which is easily achievable in either an old house or a new build.

So you're one of those people who'd rather spend 6 figures per house rebuilding than 3-4 figures insulating. The crass foolishness of such a blanket policy has been seen before. There are always some cases where it makes sense due to other factors, but as a blanket policy its just foolish and destructive.

And fwiw, the vast majority of developers either don't have imagination and flair, or more often arent willing to spend the extra to achieve it. And of course BR and planning heavily restrict attempts to make houses nicer or better featured. We have to live with the reality of these issues rather than a dream.

ditto new builds - so what

I'd say that viewpoint is well cobbled.

If you look at the market value of old versus new buildings you'll notice your view is massively outvoted.

Challenging your illogic doesn't mean I like hovels. Thats just more illogic.

Populations occasionally leave an area, and what remains isnt worth investing in... I dont know what you think that proves.

About 20 million Brits live in such old houses, and most of them work fine. Their market value reflects that fact.

Yes, we upgrade houses at times. Showers, internet, insulation... Just because your old house was a complete mess doesnt mean all others are.

NT

Reply to
meow2222
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In message , snipped-for-privacy@care2.com writes

Massive snip!

May I offer to hold your coats:-)

No sooner had the compressor started up to begin removing the concrete floor in my Victorian barn than the planning enforcement officer was along to do battle for the nimbies.

In fact he readily agreed that as it is agricultural and not listed there was no interest from town planning.

However, it is an excellent argument for what you are both saying. A century or so of alterations as farming needs changed has wrecked what might have been a sound building. The question now is whether I can afford to re-work the structure up to modern standards with a realistic pay back or retain a two storey stable block 10m from my front door.

regards

Reply to
Tim Lamb

No such thing as penetrating damp then. Is that part of the new wave thinking over at Periods.com?

Unless you're running a laundry with the windows closed, the humidity of a normal house is below the outdoor level. A building centrally heated to 18 deg C will be short of moisture during the winter. If you've ever worked in a modern office, you'll be familiar with the static build-up because of low humidity despite all those humans breathing (often heavily).

You still don't seem to have grasped the difference between water and water vapour. Materials that stop rain pouring in don't necessarily prevent vapour getting out.

Reply to
Stuart Noble

Even in those cases, the net flow of water vapour must still be from interior to exterior, it it werent the house would flood. Do you understand why?

If you mean lower RH, yes. If you mean weight of water vapour per cubic metre of air, its higher. Interior/exterior air exchange is an important mechanism for getting rid of interior vapour, even in a cold wet winter. Air holds much more water vapour as temp increases, and RH is a measure of the level of saturation, not of grams per cubic metre. If you take damp cold outdoor air and warm it to 20C, RH drops and it feels dry.

Right. Your point is?

strange thing to say

Indeed, but some do, and some have caused many a problem.

NT

Reply to
meow2222

I didnt realise youd grasped that little.

NT

Reply to
meow2222

No, and I don't see how it's relevant. What we are concerned with is water pissing through the walls, not relatively small amounts of vapour going in or out.

It doesn't matter how much moisture is in the air as long as the air is warm enough to support it. In a normal house this shouldn't be an issue.

I would have thought the point was clear. Moisture generated from the inside isn't sufficient to satisfy the requirements of warm air in winter, hence there is no movement of moisture outwards.

Can you think of a material that vapour doesn't waltz through with ease? Certainly not anything cement based. Possibly the spray on, never paint again, acrylic coatings. I've seen examples of water trapped behind those, but I've also seen them rock solid after 20 years. My hunch is that they work best when the brickwork was sound and they weren't required anyway. Even so, the coating has remained intact and the buildings haven't suffered. In other words they fail because rainwater gets behind them, not because of the migration of vapour.

Reply to
Stuart Noble

I really think you need to answer that if you're to have any credibility

Reply to
Stuart Noble

Theres no question there... and no real point

NT

Reply to
meow2222

Its key to understanding how old houses handle damp.

Lets put it another way... imagine we sealed a house up 100% water & vapour tight. Imagine occupants could continue breathing. Now, they're breathing out water vapour day & night. In a sealed container that will condense, run down the walls, and the house would gradually fill up with water.

The point here is that every house, without exception, necessarily has a net flow of water vapour from interior to exterior. If it didnt, the above would happen. Its simply not possible for a habitable building to have a net flow of water vapour from exterior to interior over any significant amount of time.

no, we're not. Everything I've said assumes any holes with water pissing in either dont exist or have been repaired. If you have a hole like that the rest is moot.

It does. If RH is 80%, condensation happens, plus it feels uncomfortable, plus moulds etc proliferate etc.

Obviously. And obviously sometimes it is.

that doesnt make sense. Warm air doesnt require moisture.

and thats illogical. Where do you think all that water vapour goes if not outside? Do you think interior RH increases forever without problem? Do you think the water vapour somehow ceases to exist? It has to get outside one way or another, theres simply no other possibility.

Yes, even painted cement has not enough vapour permeability for some situations. Cement rendered earth walls are a classic nightmare combination for exactly this reason.

NT

Reply to
meow2222

Thats why you have ventilation, dear lisa.

No it isn't, because now we have ventilation, there is no way for water to get into the structure except via water pissing in.

No, it doesn't. It has to be 100% at the point it occurs. That is the definition.

No, they do not. They need actual wet structures, not just warm wet air.

Not if it has adequate heating and ventilation, or adequate insulation and ventilation and less heating.

Makes perfect sense to me. Ventilation introduces air with a very low moisture content, even if outside is 70% RH, heating it lowers RH to maybe less than 15%. It feels dry and needs extra moisture to feel comfortable. You do that by restricting ventilation to allow a bit of steaminess to build up.

Ventilation dear lisa.

Not really. The key is that you need ventilation in all structures, and some heat. That carries way all the moisture. Then you can make the structure as impermeable as you like: In fact a modern house is gas tight to an extent. The ultimate aim of insulation in a modern house is to render it with a very low leakage of both heat and air (draught suppression) and then strictly control ventilation to the absolute minimum for sensible air replacements. In a house built to modern specifications this ventilation is THE dominant heat loss.

And once you do that you need to make the interior walls completely impermeable with foiled board etc to prevent ANY internal moisture travelling to the far side of the insulation, where the structure is cold and therefore condensation possible.

None of the *internal* moisture ever goes NEAR the structure.

Now this is basically what you have to do to get an old house to be insulated. You have no other option.

What may or may not become a problem then is ingress of external water into the structure, and failure to remove it from there.

You cvabnt rely on sucking the water into the house and up a chimney, and you may or may not be able to let it breathe outwards. However, the key to thi sis simply that it has to get out as afst as it gets in. Then all is happiness. You do that either by stopping it getting in with various things like rooves, damp proof courses and damp proof render, or if these aren't working, or don't exist, you have to let it breathe out.

A classic case is an oak frame on a brick plinth with no DPC. render that outside, and rising damp simply ends up inside the house an in the sole plates. You should inject it before rendering it, and then the very little that dies get in, doesn't travel up the sole plate - it simply evaporates from the interior to to the underfloor space below the injection level.

Reply to
The Natural Philosopher

The occupants would presumably be introducing drinking water from outside, so it would hardly be a sealed container. Otherwise, no condensation if the air was warm enough

You don't need holes in the wall, you just need a 9" brick wall with what was lime mortar, but is now a crumbling pile of powder. You cannot repair the mortar in a Victorian house without knocking it down first

Not true. We regularly have 80% RH in a hot summer and the clothes on the washing line dry in an hour. Consider that tropical timber often dries too quickly in virtually 100% RH conditions if the temperature is high enough.

Let's just say it will take it from anywhere it can. What happens to your body in a sauna? Don't answer that.

If you're generating that much moisture, open the bloody window for chrissake. Mostly the moisture you breathe in is the same as the moisture you breathe out. Your body doesn't manufacture it

Well, if you're going to live in a mud hut you have to accept the consequences.

Reply to
Stuart Noble

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