Newly made oak windows and condensation

[Jacob]

Another point about the usual uPVC windows - they look bloody horrible!

We've got 200/300 year old cottages in this village with casement DG windows with those awful mitred corners and they stick out like a sore thumb!

I agree on period properties they look out of place, especially in white.

Even worse in imitation timber effect.

 

[bugbear]

In any case it will only work when condensation is imminent due to temperature/humidity differences i.e. it stops working when you don't need it.

That a little overstated (one might go so far as to say "wrong").

One would like the dehumidification process to be controlled by room temperature and humidity (to give constant relative humidity), but external temperature obviously has a massive effect (that's where the temperature difference driving the condensation comes from).

The process is not purely passive (or free), of course, since it's driven by heat from your boiler being pumped to the outside world.

BugBear

 

[Jacob]

In any case it will only work when condensation is imminent due to temperature/humidity differences i.e. it stops working when you don't need it.

That a little overstated (one might go so far as to say "wrong").

One would like the dehumidification process to be controlled by room temperature and humidity (to give constant relative humidity), but external temperature obviously has a massive effect (that's where the temperature difference driving the condensation comes from).

Hmm, you are confused again BB

The process is not purely passive (or free), of course, since it's driven by heat from your boiler being pumped to the outside world.

BugBear

It's passive in that you don't have to switch anything on, or do anything, and it's free in that unless you close the curtains etc the window is functioning primarily as a window with dehumidification as an incidental. Doesn't require heat - it happens in unheated rooms too as internal temps (and humidity) are usually higher for a number of reasons - not least the lag in internal cooling as external temps fall nocturnally.
But it does entail heat loss as I said earlier.

 

[bugbear]

In any case it will only work when condensation is imminent due to temperature/humidity differences i.e. it stops working when you don't need it.

That a little overstated (one might go so far as to say "wrong").

One would like the dehumidification process to be controlled by room temperature and humidity (to give constant relative humidity), but external temperature obviously has a massive effect (that's where the temperature difference driving the condensation comes from).

Hmm, you are confused again BB

I would welcome argument as to my confusion, based on facts and reasoning.

Bugear

 

[Lons]

I've resisted so far in posting on 5 page thread filled with rubbish comments from someone who really should know better. To state several times, as a matter of fact that PVCu frames have weep holes to drain condensation to the outside and eventually when challenged to admit he hasn't been anywhere near a plastic window is laughable (and typical :lol: ). Also of no help whatsovever.
Either do some thorough research first Jacob or stick to those subjects within your considerable experience please.

Old buildings had loads of condensation and needed those weep channels which were developed out of necessity, but... less condensation than they could have potentially had purely because they were not insulated, were draughty, and importantly...had open fires. The key is and always will be adequate ventilation.

The ongoing regulations and energy costs have pushed energy saving and enforced more and more loft and cavity wall insulation and double glazing, (low emmisivity glass is not just desirable, it's mandatory in new installations which is why it is a notifiable works for the purpose of building regs). The regs are equally strict regarding ventilation because the more a property is wrapped up, the more condensation becomes a problem and allowing it to stream down even one window is not a solution. Try wearing a bin bag under an overcoat outside in winter and it will feel like a sauna (I haven't btw :lol: ) Gortex fabric helps clothing as breathable membrane helps buildings but it isn't a total solution just part of the equation.
Modern houses have the washing machines, tumble dryers, steamer / pressure cookers, steam irons, steam floor cleaners, power showers etc. plus vapour breathing residents with nowhere for the vapour to go otherwise (no chimney drawing air upwards). Victorians bathed once a week or less not every day if my history knowledge is correct. It's astonishing how much steam comes from a shower or bath.

I've fitted many hundreds of PVCu windows, doors and conservatories in the last 15 years. In that time have had only one glass falure which was within months due to faulty manufacture (and a hell of a lot quicker to replace than one sealed into a timber frame BTW). Not a single frame failure or complaint from any of my customers, most of whom I do a lot of other work for.
Oh and like MMUK, I fit only decent quality frames and have never implied enrgy saving as a selling point. I don't "sell" them though just supply and fit when asked

My own house is quite exposed, has 250mm loft and full cavity insulation. I replaced 22 windows in my own house more than 10 years ago and they are absolutely fine. I have no condensation problems even though the heating is on only from 4pm to 10.30 pm and none in the mornings. We sleep with a window open and have an open fire. Showers have direct extraction above and likewise cooker and utility and the tumble dryer which is rarely used is properly vented through an outside wall. We also leave all downstairs internal doors open plus unused bedrooms for air circulation.

I'd follow the advice of a dehumidifyer for a while and seriously look at trickle vents / extractor and leaving windows open on the ventilation settin - thats waht it's there for.
Also, there will be differences in the windows depending on the position in relation to incement weather. North / East will be worse than South / West which will benefit from natural heat gain.

Bob

 

[Graham Orm]

Spot on Bob =D>

 

[Jacob]

Yes to ventilation. It is essential. We are looking at the Passivent system. But also yes to draining condensation away - it's just common sense.
But plastic windows are garbage IMHO. Good to see that our plastic window men are acknowledging that DG isn't cost effective in terms of energy saving. Not many people realise this.

PS I didn't realise that PVCu frames didn't have have weep holes to drain condensation to the outside. Well they should have - such a simple and effective design solution to a simple problem.

 

[Lons]

Yes to ventilation. It is essential. We are looking at the Passivent system. But also yes to draining condensation away - it's just common sense.
But plastic windows are garbage IMHO. Good to see that our plastic window men are acknowledging that DG isn't cost effective in terms of energy saving. Not many people realise this.

PS I didn't realise that PVCu frames didn't have have weep holes to drain condensation to the outside. Well they should have - such a simple and effective design solution to a simple problem.

*No to draining condensation away on PVCu. Not really necessary if ventilation / heat balance is right. Just because it works on your ancient structure doesn't make it right for todays houses. Progress isn't all bad Jacob. After all you, I and millions of others would be in our graves by now if it wasn't for medical progress. ALL progress isn't necessarily good either of course as much is purely financially driven downwards in quality.

** I'm not one of the "plastic window men", whatever you mean by that in your usual higher than thou tone. I'm happy to fit timber windows and doors where requested (and do so). I fit what my customers ask for, give ACCURATE advice where necessary based on genuine knowledge and experience and don't push either down anyones throat. The fact I've fitted so many is down to supply and demand - nothing else. Makes no difference to me as it doesn't affect my profit margins anyway.

*** Neither I or anyone else said that "DG isn't cost effective in energy saving". Of course it is as part of the overall picture and by stating that you are advocating single glazing for timber windows as well. Absolute cr*p Jacob which is why DG units incorporating "K" type glass is a pre-requisite for building regs. The cost of a unit has dropped considerably over the years in real terms and an additional bebefit is that it's more difficult for undesirables to break through without alerting neighbours.

**** "But plastic windows are garbage IMHO" Your statements that you didn't know about the weep holes and that you haven't been near a pvc window suggest quite clearly that it's a subject in which your knowledge and experience are sadly lacking and that you're drawing your conclusions from hearsay and misguided reading.

***** "Well they should have - such a simple and effective design solution to a simple problem". Brings back memories of my son when he was 6 or 7 years old. Had some great therories which he stated as fact and was very entertaining but he too was just making it up as he went along. :lol: :lol:

Bob

 

[Jacob]

Why is it that nearly every thread that is 3 or more pages long has Jacob arguing with someone?.........

Good question! I seem to be pursued by a little angry brigade, wherever I go. I don't argue with them - they argue with me. Good job I'm insensitive and have a thick skin. :lol: Mildly amusing though.

 

[bugbear]

I don't argue with them - they argue with me. Good job I'm insensitive and have a thick skin.

All true. You don't argue. You assert without evidence or reasoning. You should try listening to other people
and responding to what they say. It's called a discussion forum, not a pronouncement forum,

BugBear

 

[Jacob]

:lol: :lol: See what I mean?

 

[Graham Orm]

:lol: :lol: See what I mean?

No

 

[MMUK]

:lol: :lol: See what I mean?

He wasn't arguing with you, merely stating a fact :wink:

 

[Lons]

My 6 year old did that as well when he was challenged - spat out his dummy :lol: :lol: :lol:

He grew up by the age of 10 though :wink:

Bob

 

[MMUK]

:lol:

 

[gardenshed]

Hi All,
The windows went together well and after glue up I fitted Aquamac 63 seal where the sash closed against the frame. The double glazing (4,14,6 Pilkington K) was installed using a soft rubber self-adhesive seal that was recommended specifically for wooden windows. The oak was treated with Sikkens Cetol as a base coat then a coat of Osmo UV protection was applied after about a week.
Thanks,
Paul.

Maybe I've missed this in the various above posts, but why are you installing K Glass & only 14mm spacers.

FWIW Pilkington K glass is old hat, it's yesterdays good technology but it's been superseded by all the other manufacturers for some time now.

As your making the windows yourself why not use the standard 20mm spacer as the PVC window manufacturers use nowadays.

If the above doesn't help your condensation problem it will certainly improve the the thermal efficiency of your house for a very small increase in costs.

HTH.

 

[MMUK]

Aye Pilks K is very old fashioned nowadays. Planitherm is the "in" thing now.

 

[ja2_k]

Aye Pilks K is very old fashioned nowadays. Planitherm is the "in" thing now.

whats the difference ?

 

[Jacob]

Just been going over the above. It seems that the solutions on offer mostly involve powered input - heat exchangers, de-humidifiers, pumped air systems. And/or passive ventilation - open fire, trickle vents open windows/doors. All these involve heat loss by air exchange, and energy consumption where powered.
So I'm happy with my plan A, which is to permit condensation but drain it, and at the same time have a passive ventilation system - namely the "Passivent". It's a trade-off whichever you do but this could be the most economical and energy saving.
With hindsight I would have modified my window designs to shed condensation more easily as there are flats on glazing bars where water will pool. But we haven't installed the Passivent system yet so it will be interesting to see how it works re condensation - the controls are humidity activated.

"Passivent" is much the same as wellywood's "positive pressure ventilation system" except in reverse and no power input - negative pressure ventilation powered by convection and the ridge effect on the roof.
In fact a "positive pressure ventilation system" would work exactly the same with the fan reversed - either way you are exchanging internal air with external air, but in opposite directions.

PS to the angry brigade - could you please not bother chipping in on this, it's so pointless, tedious and distracting, when you are trying to have in intelligent discussion.

 

[bugbear]

Thinking about the physics of all this, it's interesting that cars (at least modern ones) don't have loads of condensation on their windows, despite there being no double or triple glazed cars that I'm aware of, and the effect of external cold air being massively exaggerated by windchill, and the people/space ratio being far higher than a house, so more moisture do deal with.

I assume this is down to the heating and ventilation (what else could it be).

Does anybody understand it in more detail?

BugBear