Laura

What order to insulate in?

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We are buying an end of terrace Victorian house, it was a corner shop, so isn’t standard layout, it has 4 similar size rooms downstairs and 4 bedrooms along a long corridor upstairs, plus a shower room and bathroom bolted on the back.

 

It needs new windows and as much insulation as I can add, especially along the long north-facing outside wall. I will do underfloor and loft insulation myself (assuming it's reasonably straight-forward!), but what order do I do everything in? Windows and floors before walls?

 

And should I add piping for underfloor heating while I've got the floorboards up? Radiators will all have to come off the walls to do internal wall insulation anyway... Does UFH even work with old floor boards?

 

Top tips would be much appreciated, thanks!

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moved this from your other thread

 

"Thanks John, damp is a concern. There is a tiled gutter along the ground between the two down pipes, maybe we should extend that. I quizzed the tenants when we looked round it, they reckon it isn’t damp, hopefully our surveyor will agree! I’m hoping that there’s a bit of a gap (just a foot or so) under the floor beams, it sounds pretty hollow".

 

do not rely on the surveyor if all he being paid for is for a mortage application 

need a much more in depth look  then they ever give .the fact you know someone has made a half an attempt  tells you there is a problem and needs sorting right first time

get professional advice now as how to cure it 

.my guess its tanking brick work and pouring new concrete floor with a DPC.stud walls with vapour barriers +thick insulated plaster board and leave an air gap from top to bottom behind walls into roof space/soffits for ventilation 

--i could be talking crap --get professional help now  before spending any money 

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The old Victorian terraces in my experience (I have a couple circa 1860) were built draughty by design. 

 

Key features were:

 

- Suspended wooden floors with air bricks. Basically timber joists on brick dwarf walls. A big void often down to the "dirt". This allowed good, cross ventilation, front to back that kept the floor joists from rotting. 

 

- Solid brick walls with a slate damp course

 

- Lime mortar

 

- Lath and plaster ceilings

& sometimes walls

 

- Horse hair plaster again with a high lime content.

 

- Proper timber floor boards with the gaps plugged with hemp string. Kept the major draughts out but still allowed plenty of ventilation.

 

- Open chimneys. Again a good ventilation route.

 

- Wooden windows, very air leaky.

 

- Timber lintels

 

Modern faux pas are: 

- to fit double glazing with no trickle vents.

- to block up the air bricks 

- to block up the chimney

- to render over the slate damp course

- to bring the ground level up over the damp course

- to put an extension on the back / porch on the front covering the air bricks / damp course.

 

These old houses are meant to breathe to stay dry and mould free. You can as John alludes to "upgrade" the place but must pay very close attention to ventilation.

Edited by Onoff
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You need to consider whether this is your "forever" house and if not whether the improvements to a period place will increase it's value when you want to sell. You can do too much. Of course if you can do the work yourselves then that might make the sums add up.

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Thank you Onoff, really useful pointers. I don't think any of those faux pas have been committed yet, so will try to keep it that way. We have a proper building survey being done in the coming week.

 

I think it's a forever home, we certainly want it to be comfortable. Will do as much of the work as I'm able to, but defer to experts on things like the internal wall insulation - from what I've read that's fraught with damp causing potential...

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Sounds a good size place. 

 

The thread before yours in this section has @zoothorn looking at digging up his concrete floor in his old stone cottage and building back up an insulated floor with UFH. I've done similar in my bathroom and some key pics are there. That's one option for you with the added benefit that once the timber floors are gone the "digging" will be done. There's other options of course. @Ferdinand with his Little Brown Bungalow thread I think insulated an existing suspended floor.

 

 

That didn't have UFH but there are options to incorporate UFH pipes in special grooved floor boards, aluminium spreader plates etc.

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I agree with OnOff's key features above.  We renovated an end terrace house and it had several of those issues.  Damp was certainly a problem as previous owners had used cement render over the lime mortared walls.  so where the render had cracked or was damaged, water was getting in but could not get back out again.  Not sure if it will help but our blog will give you some ideas of what to expect.

 

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Good luck with the renovation - you have come to the right place for advice.😀

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@Laura some general advice.

 

A key principle I learnt from reading the Passive House Handbook is that it is interstitial moisture which destroys buildings

 

If you add insulation, you may be lulled into thinking that you can only be doing good. However you would be well advised to focus on how moisture (both liquid and gaseous) moves through walls and how adding the insulation affects that. Specialists can model this for you. 

 

As @Onoff says:

 

3 hours ago, Onoff said:

These old houses are meant to breathe to stay dry

 

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Thanks all, top tips. I’ll be seeking a specialist quote for internal wall insulation before the purchase is complete, and definitely getting a specialist in to do it, I like the idea that it can be modelled rather than just sticking a finger in the air to figure out the dew point.

 

If we were to do windows, underfloor and walls do you reckon it’d be in that order? I know the internal wall insulation is easily damaged by things penetrating the vapour layer, so I’d guess it wouldn’t be very clever to put in new windows afterwards?!

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12 minutes ago, Laura said:

Thanks all, top tips. I’ll be seeking a specialist quote for internal wall insulation before the purchase is complete, and definitely getting a specialist in to do it, I like the idea that it can be modelled rather than just sticking a finger in the air to figure out the dew point.

 

If we were to do windows, underfloor and walls do you reckon it’d be in that order? I know the internal wall insulation is easily damaged by things penetrating the vapour layer, so I’d guess it wouldn’t be very clever to put in new windows afterwards?!

 

Before going mad what's the roof like? Get that in good order or it has the potential to ruin everything else. Also you'll be looking to use airtight tape around the windows if you door properly. 

 

If you're going that far worrying about insulation and air tightness are you considering MVHR?

 

 

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14 minutes ago, Onoff said:

 

Before going mad what's the roof like? Get that in good order or it has the potential to ruin everything else. Also you'll be looking to use airtight tape around the windows if you door properly. 

 

If you're going that far worrying about insulation and air tightness are you considering MVHR?

 

 

See, I’m at the stage where I don’t really know what’s mad and what’s achievable! I like the idea of MVHR, but suspect that’s on the mad side for a large-ish old house...

 

The roof is in pretty good nick, I stuck my head up in the loft, it smells dry andthe underside of the tiles is lined with a bitumen felt. It looks to have been redone at the same time as the rest of the terrace. (No bats, which I’m slightly sad about, but it’s probably a good thing really!)

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Better people than me to advise but think about it from this angle: Seal that old house up tight and insulate without ventilation and you'll have no end of condensation and mould issues plus it won't be a very pleasant place to live. So you will need to ventilator. With MVHR you can recover something like 70-90% of the heat vented out.

 

Worth a read:

 

https://passipedia.org/planning/refurbishment_with_passive_house_components

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Ever heard of the EnerPHit standard? If your budget can stretch to having an architect, you could consider a full refurbishment to the highest levels of airtightness and thermal performance.

Edited by Dreadnaught

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1 minute ago, Dreadnaught said:

Ever heard to he EnerPhit standard? If your budget can stretch to having an architect, you could consider a full refurbishment to the highest levels of airtightness and thermal performance.

 

All on my link.

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14 hours ago, Laura said:

And should I add piping for underfloor heating while I've got the floorboards up? Radiators will all have to come off the walls to do internal wall insulation anyway... Does UFH even work with old floor boards?

UFH is a can of worms in a retrofit. Be very wary of what youll do to keep the place warm if youre not going to remove the wooden floors ( joists and all, eg nothing between you and the dirt ) and insulate under a new slab. You can insulate under the joists a little and then insulate between the joists, and then you can lay aluminium spreader plates directly underneath the floorboards which will work.

If you zoom in you can see the shiny aluminium panels with the two indents for a piece of 16mm pipe to sit in.

IMG_8056.thumb.JPG.52da11e293fb4033ce93a318fb50f91f.JPG

 

This really is a question of how far you can improve the building in order for UFH to become suitable. A house like this would normally need high temp emitters such as radiators, which quickly change cold air into warm air and circulate it around the room whilst doing so.

LOTS to consider before even thinking about UFH ;)

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On 12/01/2019 at 08:28, Laura said:

We are buying an end of terrace Victorian house, it was a corner shop, so isn’t standard layout, it has 4 similar size rooms downstairs and 4 bedrooms along a long corridor upstairs, plus a shower room and bathroom bolted on the back.

 

It needs new windows and as much insulation as I can add, especially along the long north-facing outside wall. I will do underfloor and loft insulation myself (assuming it's reasonably straight-forward!), but what order do I do everything in? Windows and floors before walls?

 

And should I add piping for underfloor heating while I've got the floorboards up? Radiators will all have to come off the walls to do internal wall insulation anyway... Does UFH even work with old floor boards?

 

Top tips would be much appreciated, thanks!

IMG-20181216-WA0000.jpg

 

You are not clear whether this is 1 - A flip and sell, 2 - A short term (<5 year) investent, 3 - A long term investment, or 4 - Somewhere to live for the short term, or 5 - Somewhere to live long-term.

 

That affects things significantly.

 

I have recently been investing for the long term (=10-25 years), though could sell earlier, which means I have an eye on what the standards will be in say 2030, and how I want to balance off more investment now against whether my typical tenancies will be 1-2 years or 6-10 years. I have turned down possible purchase of several renovated properties on the basis that the basic work (eg IWI or UFI) has been done, or not done, to a poor or typical standard, and that money has been spent on making it posh no top of that, so that the net result has been a tarted-up old house that will need to be fundamentally gutted in 10 years time in order for it to be legal in 15 years time a rental.

 

IMO You can sell lower standard refurbs more easily to owner occupiers than to knowledgeable people who will rent it out, because required minimum standards are higher in rentals than Owner Occupied dwellings even now.

 

I think you need to take time to look at your overall goals and how to get there before you do anything. The problem is that you are presumably already paying Full Council Tax on it !

 

My normal current mix for long-term investments is roughly:

  • Target at least current Building Regs standard, and an EPC C grade.
  • Do Underfloor insulation anyway if a long term refurb. 
  • Do IWI if solid walls, with 50mm or 75mm of Celotex or PIR insulation. That is, highly insulating stuff. Smaller rooms reduces sale price.
  • Do not necessarily do IWI if cavity wall where cavities have been filled.
  • Fit good well-sealed windows - better quality 2G.
  • Do Underfloor Insulation of some sort if floating floor. On slab insulation if solid floor - but needs to be quite tactical wrt door, ceiling height.
  • Bring services inside the insulated envelope. The last one I ran them in voids in a floating floor. Not sure about this yet.
  • 250mm loft insulation - usually done for free. If too much insulation in loft to get it free, but less than required, use existing loft insulation to insulate under floor if possible. 
  • Obsessive attention to detail wrt gaps etc.
  • Deal with ventilation separately, usually via a loft-fan (Nuaire etc), and an outlet fan or two on permanent trickle, either HR (Heat Recover) or not HR.
  • My next one I will probably use UFH and a boiler that modulates down, or a ASHP if I can be confident enough.

The usuals - Rewire, Replumb, Kitchen, Bathroom, Plaster, Redec etc are much more run of the mill stuff.

 

Assuming no pratfalls on your part, that mix seems to keep Ts happy and deliver bills around half what they would be in a non-renovated house. The question is whether that matches your identified goals.

 

Tenant management is an entirely different shark-infested custard.

 

Ferdinand

 

Edited by Ferdinand
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Brill, thanks all, that helps clear my head a bit. I think this one is a reasonably long-term home for us, so we’ll do a sensible amount of insulation without going OTT. I especially like the idea of using loft insulation under the floors to help qualify for free loft insulation! That passivhaus stuff is fascinating, but probably not us this time... I love the character of this new house, definitely wouldn’t want to stop it breathing!

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42 minutes ago, Laura said:

Brill, thanks all, that helps clear my head a bit. I think this one is a reasonably long-term home for us, so we’ll do a sensible amount of insulation without going OTT. I especially like the idea of using loft insulation under the floors to help qualify for free loft insulation! That passivhaus stuff is fascinating, but probably not us this time... I love the character of this new house, definitely wouldn’t want to stop it breathing!

 

How are you going to calibrate your concepts of "sensible" and "OTT"?

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7 hours ago, Ferdinand said:

 

How are you going to calibrate your concepts of "sensible" and "OTT"?

By obsessively reading up on it, looking at my bank balance, talking to our friendly RICS surveyor, and watching for raised eyebrows (and whatever the online equivalent is) whenever I talk to others about it. You lot are helping broaden my thinking on the subject! 

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10 hours ago, Laura said:

By obsessively reading up on it, looking at my bank balance, talking to our friendly RICS surveyor, and watching for raised eyebrows (and whatever the online equivalent is) whenever I talk to others about it. You lot are helping broaden my thinking on the subject! 

 

Heh.

 

Also bear in mind that there are some cost-saving threads around, so you can probably get up to a third more material for the price you first look up in Wickes, and that it is also useful to do a heat model on the famous @JSHarris spreadsheet, and that it is worth taking a few years .. say 10 ... heating bills into account for your lifecycle cost.

 

eg 

 

 

You can get a routine 10-20% off at Wickes itself with a Trade Accoutn and a Reloadable Cash Card, for example.

 

The thing about the fabric improvements is that you only get the chance to do them once, and only have to pay for them once, so some bullet-biting helps. it particularly helps when you are half under a floor at arms length with a staple gun.

 

F

Edited by Ferdinand
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Brilliant, thank you. A way to save pennies on materials is most welcome, and I’m looking forward to testing out that spreadsheet when I get a mo, I do love a good spreadsheet, and seems an ideal way to weigh up our options!

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As far been said many times in here...You only pay for insulation ONCE! 

 

As in put enough in & do it right and it'll serve you well and as fuel costs double, triple, quadruple the impact will affect you less.

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Yep, insulation and PV are amongst the few index-linked pensions available to most of us.

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4 hours ago, Laura said:

Brilliant, thank you. A way to save pennies on materials is most welcome, and I’m looking forward to testing out that spreadsheet when I get a mo, I do love a good spreadsheet, and seems an ideal way to weigh up our options!

 

IMO really work at it and you can save enough on materials to cover quite a lot of specialist Labour.

 

Obvs it depends what you compare it with, but I think that 25-35% is possible as an average. I tend to use Wickes retail prices as a benchmark.

 

F

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