New member - stuck for what to do next to warm the house

[Sparrowhawk]

Blower door in action for the first time. I was pleasantly surprised by how airtight the main rooms downstairs were (I sealed the dining room door into the hall, and mounted the blower door into the lounge doorway into the hall). Even on the slowest setting the fan created enough pressure difference to find the major leaks, with the next speed up used for the smaller ones.

 

 

Now to start sealing the 40ish leaks we identified!

Edited February 25, 2023 by Sparrowhawk

[Iceverge]

Top Class. 

 

Keep up the good work. 

[Sparrowhawk]

I had little time last month but chased down a few air leaks, and I modelled the 1st floor room my wife uses as an office - model here with comments to explain each sheet. Anything look off in it?

 

I did this thinking I could work out if the room is cold due to fabric or airtightness heat loss (I failed), but it's been helpful to see which bits of fabric are particularly bad and I'm now using it to plan what improvements to make.

 

Some wins are clear - loft insulation (as much as the water tanks in the loft above this room will allow) and CWI (planned but later).

 

Others such as replacing the 50mm of likely-badly-installed PIR in the sloping ceiling seem less clear cut. Due to restricted headroom I can't put more than 10mm insulation below the rafters so 100mm PIR between rafters is most I'd be able to fit. It should help with making sure there's no thermal bridging round the window and radiative comfort as my wife has her desk below it but is also disruptive.

 

What do you think the actual u-value of that sloping roof is vs the theoretical value?

And in your view worth doing or the effort better spent elsewhere e.g. IWI on the external walls?

 

Edited April 2, 2023 by Sparrowhawk

[ProDave]

Those cupboards into the eaves under the window ring alarm bells.  Anything similar I have seen is poorly insulated if at all and leaks like a sieve.  Get your blower door on that room and I bet you will find howling cold gales coming in there.  That looks like an access trap into a crawl space to the right of the cupboards, again likely to be poorly insulated and draughty.  But put your head in there with a torch and you will get a good idea of the quality or otherwise of insulation and detailing there.  Take some pictures and post them.

 

The other common detail I often come across is you take a socket or switch off the wall on a windy day and get a cold icy draught coming out of the hole, meaning detailing is poor and cold air is able to get where it should not, and I am talking about switches on internal walls here.  What should be simple tings like sealing cable holes from a cold loft down into an internal stud wall.

[SteamyTea]

I assume there are 3 pillars, and two separate 'triangles'.

Apart from calling the power, energy, it seems about right.

Actually it seems very good.

Amazing how the losses soon add up the isn't it.

Still 300W is not dreadful, a small fan heater on 20 minutes every hour.

[Sparrowhawk]

Photos first then replies!

 

General ones to give a feel for the room. The green painted part is in the 1920s house, the white the 1997 extension.

 

The piece of loose MDF is where I knocked out a built-in cupboard to make space for the desk and open up the room. I have done a lot of taping in the eaves storage to reduce draughts as it was like a colandar when we moved in. I presume the PIR behind the plasterboard ceiling is just as bad.

Sealing the draughts at the top of the cupboard - to the windowsill, all along the ceiling edge - has gone poorly. I tried foam with an extension tube, caulk, and most recently Tescon Vana tape. Getting anything tight into the point of a triangle is tricky.

 

On the opposite side to the bit I knocked out is the hot water tank. Note the pipes that disappear into the ceiling and run up - above the insulation - into the loft. WTF are there 4 of them (3 here, 1 from top of hot water tank) and not just 2?

 

The neighbouring room has the same construction and eaves storage. I've emptied it to experiment and take up the flooring, and here are photos:

 

I forgot to annotate that air leaks at the wall straps, because they create a gap around the insulation and it's impossible to seal properly. I'm not clear if I could do better taking out the PIR and replacing it - the wall plate interface is always going to be a weak point with poor contact.

[Sparrowhawk]

5 hours ago, ProDave said:

Get your blower door on that room and I bet you will find howling cold gales coming in there. 

 

It is draughty but a lot better than when it started! The problem now is that apart from the rafter joist ends (photo below) it's become difficult to track down the rest. Even at the top where the cupboard meets the plasterboard ceiling and there's a cold draught, but none stands out as bad bad. I suspect it's the good old 0.1mm (max) wide gap, but in multiple places and each 2.5m+ long.

 

Here's a rafter/wall plate photo I left out of the previous post. There's 18 rafters at 30-36cm centres, and some are worse than this one.

 

5 hours ago, ProDave said:

The other common detail I often come across is you take a socket or switch off the wall on a windy day and get a cold icy draught coming out of the hole, meaning detailing is poor and cold air is able to get where it should not, and I am talking about switches on internal walls here.  What should be simple tings like sealing cable holes from a cold loft down into an internal stud wall.

Yes I've had those too! Plus we have that where the central heating pipes come up through the floor, even against internal walls. I have to lift some of this floor before the structural engineer visits in 2 weeks so will be interesting to see what's below.

Edited April 2, 2023 by Sparrowhawk
Rafter. I mean rafter ends, not joists

[Sparrowhawk]

3 hours ago, SteamyTea said:

I assume there are 3 pillars, and two separate 'triangles'.

Yes, hopefully the extra photos help with understanding the room.

 

3 hours ago, SteamyTea said:

Apart from calling the power, energy, it seems about right.

Awesome and thanks for the correction. Out of interest if I used Joules per second instead of Watts, would 'Energy' then be the correct term?

 

3 hours ago, SteamyTea said:

Actually it seems very good.

Amazing how the losses soon add up the isn't it.

Indeed! I was surprised at the loss through the wall from keeping the neighbouring, mostly unused room, 4C cooler.

 

3 hours ago, SteamyTea said:

Still 300W is not dreadful, a small fan heater on 20 minutes every hour.

Yes, though that is for a deltaT of 10C and with no ventilation heat loss, which at 3ach doubles the loss.

 

I started this model as I found my wife freezing in her office with a 0.5kW oil filled radiator on max and the heating running. The room wasn't getting above 15-16C (unfortunately I don't have the external temperature for that day). On a still day when it's 10C outside she says the room will reach 18-20C with just the oil filled radiator and she has to turn it down. I need to measure the energy input but first need a new energy meter plug, as the kWh recorder on mine has got stuck.

[ProDave]

All you are doing is show just how lousy the detail is on MOST houses in the UK.  You could spend a lifetime sealing each and every single hole and there will be as many more left that you can't see / reach.

 

Most on here will agree it is easy building a house from scratch to get it well insulated and air tight, by correct detailing while you have access and use of membranes, tapes and sealants where appropriate.

 

What you are showing is the outstanding problem of just how do we significantly improve the older UK housing stock (and in some cases not so old!!) that was built without such care and detail.

 

I have a friend who has been doing that to an old stone cottage with surprisingly good results, but it has been a LOT of work.  Room by room, over many years, one room at a rime he has stripped it back to a bare shell, all plasterboard off walls and ceilings and all floor boards up.  Then and only then can he seal all the poor detailing, insulate it, and finish off with an air tight membrane before re boarding and re flooring.  I doubt many want to go to those extremes?

[SteamyTea]

1 minute ago, Sparrowhawk said:

Out of interest if I used Joules per second instead of Watts, would 'Energy' then be the correct term?

Not really.

There are SI base units, kg, m, s and a few others.

From those, you can make recognised units like newtons, joules and watts

And from those, with a bit of mixing up, you get recognised units like kWh,

 

So

 

kg.m².s^-2 = J

 

kg.m².s^-2 / s = kg.m².s^-3 = W

 

 kg.m².s^-3.3600 s = 3600 kg.m².s^-2 = kWh as there is 3600 seconds in an hour.

 

In an ideal world, we would use joules for energy and watts for power, but somewhere along the line, someone thought it was a good idea to use the kWh.

That in itself is not too bad.

But, then it gets corrupted into nonsense units like Killa wots per our, which does not even make sense in English, let alone phyisics.

15 minutes ago, Sparrowhawk said:

unfortunately I don't have the external temperature for that day

Try the historical records on Weatherunderground.

You can usually find a weather station within a mile.  Some are better than others i.e. solar meter.

 

[Sparrowhawk]

22 hours ago, ProDave said:

All you are doing is show just how lousy the detail is on MOST houses in the UK.  You could spend a lifetime sealing each and every single hole and there will be as many more left that you can't see / reach.

 

Yes, and working out which are worth it and which aren't is a guessing game unless I can find a better way to quantify them and the gains.

22 hours ago, ProDave said:

I have a friend who has been doing that to an old stone cottage with surprisingly good results, but it has been a LOT of work.  Room by room, over many years, one room at a rime he has stripped it back to a bare shell, all plasterboard off walls and ceilings and all floor boards up.  Then and only then can he seal all the poor detailing, insulate it, and finish off with an air tight membrane before re boarding and re flooring.  I doubt many want to go to those extremes?

It's tempting. Floors have to be lifted to deal with the major drafts, but beyond that is a hobby/labour of love.

 

Let's say I take down this sloping ceiling and remove the current PIR. How would I make the replacement airtight at the wall plate and at the top where it enters the cold loft? I have found a lack of technical drawings for those two areas.

[SteamyTea]

2 minutes ago, Sparrowhawk said:

Let's say I take down this sloping ceiling and remove the current PIR. How would I make the replacement airtight at the wall plate and at the top where it enters the cold loft

Could you do it with a Tyvek type material?

It lets moisture out, but reduces air mass flow rate to virtually zero.

 

[Sparrowhawk]

It's been a few months since I posted. There's little progress to show but been lots of thinking going on.

 

On 06/02/2023 at 21:21, ETC said:

Sell up and move to a more energy efficient house.

 

We've been seriously thinking about this, but with nothing better coming up we've decided to stay, since most housing is the same age in this area and we reckon it will have problems. We've given ourselves 10 years before we move to another region of the UK.

 

We also worked with a local architect who offered a "love it or leave it" service. The lack of light on the north aspect annoys my wife and the room layout in the extension isn't great, so as we are planning new windows and lifting floors it seemed ideal to discuss potential remodelling, removing walls and all that kind of stuff before doing anything.

 

Said architect was most put out we aren't taking their work further, on the grounds that estimates they had asked us to get from builders were 2x-3x more than our budget (which the architect knew). And we felt their designs didn't provide what we wanted (our fault for not knowing clearly what to instruct).

 

So we're back to widening and maybe raising an opening at the back, new glazing, and back to thermal efficiency which no one I've spoken to in the last 2 months has given a damn about.

 

And now we've decided to stay I'm back to working on the house. First stop is thermal fabric modelling, and working out why the floor is 1.5 inches higher in one room than the next. My wife has asked for a crowbar and wants to start tearing the place apart...

 

And I need to decide if the cavity wall insulation companies in the area can be trusted or a complete bunch of ********. The idea of a calculation of exposure to wind-driven rain meets with blank looks.

[SteamyTea]

1 hour ago, Sparrowhawk said:

The idea of a calculation of exposure to wind-driven rain meets with blank looks.

Can you clad that side?

[Iceverge]

1 hour ago, Sparrowhawk said:

My wife has asked for a crowbar and wants to start tearing the place apart...

 

Give her a 6mm masonry bit a boroscope and a notebook first! 

 

1 hour ago, Sparrowhawk said:

And I need to decide if the cavity wall insulation companies in the area can be trusted or a complete bunch of ********. The idea of a calculation of exposure to wind-driven rain meets with blank looks.

 

EPS beads are almost idiot proof. How wide is your cavity? Is it a brick or render finish? 

[Sparrowhawk]

22 hours ago, SteamyTea said:

Can you clad that side?

Yes - it's the front and it's rendered, but cracking in places.

 

22 hours ago, Iceverge said:

Give her a 6mm masonry bit a boroscope and a notebook first!

Good thinking!

 

22 hours ago, Iceverge said:

EPS beads are almost idiot proof. How wide is your cavity? Is it a brick or render finish? 

The cavity's approx 100mm and the house is rendered in a mix of old (1920s? later?) on the front the driven rain side, and 1990s/2000s on the others. The 2000s stuff is nice render, rust marks from an idiotic choice of corner beading but no cracking or anything.

 

The challenges are:

• much house wiring in the cavity inc 80A cable between two fuse boxes (use Perlite as cavity fill? No installers use this - so will need some rewiring)
• unfilled cavities open onto partial fill with batts in the extensions (don't see the problem here, fill it all)
• internal cavity walls throughout the house (that's what lances are for or they can drill internally and we'll redecorate)
• cavities need closing at loft level (somebody else can faceplant in 1980s glass fibre to do this - or it needs scaffolding & fascias off)
• air bricks need sheething at ground level (standard requirement)
• and better do a wall tie check with the 98 year age of the house + closeness to the sea, plus check the cavity's clear of rubble

One company looked in the cavity via 2 drill holes, said it looked fine and did I want to sign the paperwork now. Given there's the original house + two extensions of different dates I thought that a bit superficial.

[MikeSharp01]

On 04/07/2023 at 20:21, Sparrowhawk said:

There's little progress to show but been lots of thinking going on.

Really thinking things through can sometimes be mistaken for procrastination but 'no', really thinking things through save heaps of trouble in the long run.

[Dave Jones]

the spray mist aerogell stuff on old housing stock could be a game changer

 

 

 

[Sparrowhawk]

First morning with internal condensation on the 2g windows.

 

8.8C minimum outside with 95% RH, internal temperatures remained above 18C and a RH of around 70%.

 

A window supplier came round to quote. Harder to get rid of than the JW's and vague when pushed on details.

[SteamyTea]

3 hours ago, Sparrowhawk said:

First morning with internal condensation on the 2g windows.

 

8.8C minimum outside with 95% RH, internal temperatures remained above 18C and a RH of around 70%.

Was that condensation on the inside?

 

[Sparrowhawk]

3 minutes ago, SteamyTea said:

Was that condensation on the inside?

It was. The dew point would be about 12.5C with those internal conditions. Condensation was in the corners of the windows (more at the bottom) & across the bottom - thermal bridging via the aluminium spacers?

[SteamyTea]

Just now, Sparrowhawk said:

thermal bridging via the aluminium spacers?

Possibly, or a leak causing very high local RH.

As you say, the internal numbers are above the dewpoint.

[Sparrowhawk]

6 minutes ago, SteamyTea said:

Possibly, or a leak causing very high local RH.

As you say, the internal numbers are above the dewpoint.

Now it's cooling outside I am hoping internal RH comes down. It's remaining stubbornly high. Since all rooms are within 10% of each other I'm assuming there's not a leak in one room adding moisture to inside as I'd expect one room to be worse than the rest.

[SteamyTea]

16 minutes ago, Sparrowhawk said:

It's remaining stubbornly high

My internal RH is generally above 65% all year round. I live in one of the wettest parts of the country though.

I can get condensation internally, seems worse behind my thermal curtains.

Could be that locally the temperature is just colder there.

Try leaving the curtains undrawn and see if the problem is still there.

 

[S2D2]

Ideally get the humidity below 60% to see if you still have an issue, 70% is too high.