Hi from Glasgow! Renovating an old terraced house

[Iain M]

Hi all,

 

We recently bought an old dilapidated house in Glasgow, with a plan to doing a deep renovation. We're luckily able to live nearby with my mum for the duration of our works, so this is our big chance to get all the major stuff done, and done properly! New windows, insulation, electrics, heating, the works. But we'll need to get our planning and build regs applications in very soon, so there's no time to waste. I'd really appreciate any advice you all have on what things we should focus on getting right, and what things can be left until later.

 

I've been bitten hard by the energy efficiency bug while doing my research, particularly around ventilation… Warning, lots of semi-informed guesswork to follow :)

 

Having lived in old houses before, it always seemed like you have to pretty much stick radiators under the windows and pump hot air out of them, otherwise you get condensation. Horribly wasteful. Then I learned about MVHR, and the idea that you can simply swap out the air but retain the heat. Wonderful! But I don't know if full MVHR is really feasible / affordable in a 100-year-old house—our architect is certainly sceptical. For example, how do you ensure good ventilation around the solid walls and under the suspended floor? Again, any advice appreciated.

 

I'm seeing ads for single-room MVHR units, which if I understand right, alternate every minute or so between extract and intake, and exchange heat that way. How well do those work, and are they cost-effective compared to ducted MVHR? The single-room units are fairly expensive and it seems like you'd have to install quite a few of them.

 

I've also discovered PIV, which sounds like it might be a cheap and simple second best. Pump in air from the attic, maintain a positive pressure so you get semi-controlled exfiltration, no infiltration. I very much like the idea of filtering the incoming air, as we're close to a busy road.

 

I've read in a few places that MVHR starts to make sense at around 3 ACH. Other than wasted money, what disadvantages do you start running into around that point? Is there such a thing as a hybrid MVHR / PIV system, where you maintain positive pressure but also recover heat where you can?

 

Thanks for listening to my rambling, if you've read this far, and I look forward to getting my skewed notions corrected. :)

 

Cheers,

 

Iain

[Onoff]

Welcome. I've spent a bit of time up in Glasgow visiting family & working.

 

Think you'll find you need really to be super insulated and near airtight to really benefit from MVHR. 

 

Now with an old house where do you add insulation to say the walls? Add it inside and lose space. Add externally and you increase the wall thickness which may be at odds with neighbouring properties if terraced. @Ferdinand I think paid particular attention on his Little Brown Bungalow refurb project to energy saving / insulation. @oranjeboom went the whole hog with EWI and digging floors deeper for UFH. Check out too @MarkyP's comments and pics on my EWI thread.

 

What type of property is you have etc? We love pictures btw!

 

 

[Iain M]

It's a mid-terrace sandstone house. Here's the estate agent's picture, on a suspiciously bright sunny day:

 

 

Definitely needs a lot of TLC inside:

 

 

That flat roof section at the front had a serious leak, which is the main reason the house was relatively affordable:

 

 

We've fixed that leak and had the timbers surveyed, and it should be safe for the winter.

 

So now we can concentrate on what kind of renovation we want. Looks like the work might divide into two parts:

- Renovate the upper floor and the front (can be started ASAP)

- New kitchen and extension at the rear (building regs required)

 

Being a mid-terrace has upsides and downsides. In terms of insulation, I think we mainly just need it at the front (since the rear extension will be to higher modern specs). So I think we just go with internal insulation and lose a little bit of length. New windows throughout, better loft insulation, and we should be in a good place.

[Ferdinand]

Welcome,  Iain.

 

8 hours ago, Iain M said:

But we'll need to get our planning and build regs applications in very soon, so there's no time to waste.

This is your biggest enemy at present. No good learning things after you have committed to, or started, a course that will prevent you doing them. So it may be a good plan to take a little more time or learn faster ?. Don't overset your expectations if you are planning a full renovation, or you might suffer from 'bugger we only just started'' syndrome at 6 months.

 

That looks like a spacious small terrace (reminds me of some of the early c1800 ones in Hammersmith), rather than one of the hoofingly-large ones that there are a lot of in Scottish cities. Your thinking is a good start, but there are some areas you need to extend it into imo.

 

Some things IMO missing so far from your list that it would be useful to know are:

 

1 - Just how far are you cutting it back ... eg are you going to brick or skimming.

2 - What are your plans for the floor wrt eg insulation?

3 - Are you in a regulated area wrt conservation etc?

4 - What are your plans for a heating system?

5 - Are youplanning solar?

 

To my eye EWI (External Wall Insulaton)  does not look feasible without doing the whole terrace, so also wrt IWI:

6 - How high are your rooms in general?

7 - Ditto the doors? Are they original and are you keeping them?

8 - How large are your rooms (ie can you afford to lose say 100mm to insulation if you need to)? Have aerogel on your radar if you just need to insulate the front wall and your rooms are small, though your bank account will know when you have bought some.

 

In terms of where to start, I would suggest a Heat Model on the @JSHarris spreadsheet (someone needs to provide a link to where it is now), and also on the ^{Stroma EPC software}. That is to understand your house, and also to know where your target is. I would recommend aiming for at least a B on EPC, as it has to be a C for future rental if that will be needed, and is a decent place to aim for.

 

If you are building a 20k-30k extension, then any extra money you spend to take your insulation from "good" to "very good" will be relatively small. ie so do it. If you sweat your extension budget just reasonably well, it should more than cover the other.

 

On MVHR, you need to consider it and balance cost against benefit (including comfort), but you do need a ventilation strategy alongside your energy strategy.

 

The ventilation strategy needs to address the extra difficulty you are causing for for both moisture and air to escape from your more sealed house, compared to the original permeable-walls-full-of-holes. That is, both heat and humidity.

 

I find big benefit from a PIV at the top of the house, and some sort of outlet (eg Heat Recovery fan with backdraft shutter in kitchen or utility, and a low volume trickle setting) at the bottom (usually kitchen). It does make a material difference, either in the case of poor glazing (even single), or with well sealed 2G or 3G, as a intermediate between trickle vents (spit!) and MVHR. It is about providing an alternate route for moisture and air now that you have significantly sealed the walls.

 

Others may argue keeping the walls permeable by choice of material as they do not like full membranes. My view is still to allow the walls to be sealed more but provide robust always on background ventilation.

 

Finall,y remember to integrate your systems in space terms, and keep them maintainable. My last one I brought all the services above the underfloor insulation and plumbing / gas / electrics into channels in the insulation in my floating floor, which I think works. Had separate rockwool insulation under the suspended floor providing an overall insulated envelope.

 

For the next one I will look very carefully at AHSP not gas, underfloor insulation, a floating-floor type underfloor heating system, and electrics running around the edge of the room under the floating floor. That will require good underfloor insulation, and careful tactical consideration for light switches etc.

 

I'll stop there, but happy to answer any questions. My renovations have been mainly rentals so robustness, maintainability and resilience are very important to me.

 

Ferdinand

 

PS You need to decide how to handle those nice windows if you put 2G or 3G in if not there already.

Edited November 6, 2018 by Ferdinand

[Jeremy Harris]

36 minutes ago, Ferdinand said:

 

In terms of where to start, I would suggest a Heat Model on the @JSHarris spreadsheet (someone needs to provide a link to where it is now),

 

Welcome Iain,

 

The spreadsheet that @Ferdinand refers to works out the total heat loss and is here: Heat loss calculator - Master.txt

 

The forum doesn't allow spreadsheet files to be uploaded, so when you've downloaded it just change the suffix from .txt to .xls and it should open OK in most spreadsheet programmes.

 

 

[Iain M]

12 hours ago, JSHarris said:

 

Welcome Iain,

 

The spreadsheet that @Ferdinand refers to works out the total heat loss and is here: Heat loss calculator - Master.txt

 

Thanks @JSHarris! I'll take a look.

[Iain M]

13 hours ago, Ferdinand said:

That looks like a spacious small terrace (reminds me of some of the early c1800 ones in Hammersmith), rather than one of the hoofingly-large ones that there are a lot of in Scottish cities.

 

Yes, it's a nice size—three bedrooms, which is all we need, but in fairly generous proportions.

 

Thanks so much for the very detailed reply! I'll answer your questions inline.

 

13 hours ago, Ferdinand said:

Your thinking is a good start, but there are some areas you need to extend it into imo.

 

Some things IMO missing so far from your list that it would be useful to know are:

 

1 - Just how far are you cutting it back ... eg are you going to brick or skimming.

2 - What are your plans for the floor wrt eg insulation?

 

Good questions, still working those out with the architect.

 

13 hours ago, Ferdinand said:

3 - Are you in a regulated area wrt conservation etc?

 

Not a conservation area, so that helps.

 

13 hours ago, Ferdinand said:

4 - What are your plans for a heating system?

 

For a heat source, a good new combi boiler is the obvious safe choice. But I'm very interested in renewable alternatives, particularly:

• Wood pellet boiler, or stove with back boiler. Wood-burning stoves are popular round here and everyone I've spoken to highly recommends them. It sounds like a good way to make use of at least one of the original fireplaces. I'm thinking pellets because the RHI is very appealing. So if we get a little pellet stove, and we're going to be buying pellets anyway, why not use them for heating and hot water? The up-front cost looks OK, not that much more than a gas combi.
• Air source heat pump—I see lots of discussion of these online but I haven't seen one in person. They sound great but the up-front cost seems to be rather high (Energy Saving Trust says in the region of £6000). So I'm thinking maybe we just give ourselves the flexibility to add one later.

To heat the house, we like the idea of underfloor heating downstairs, particularly in the kitchen. And as mentioned maybe a little wood stove for the winter.

 

Elsewhere, I suppose radiators, but I've also come across heated skirting boards, which sound very nifty! Anyone know if they're just a gimmick, or do they work well? It'd be nice not to have to lose wall space to radiators.

 

13 hours ago, Ferdinand said:

5 - Are youplanning solar?

 

Yes, definitely! But again, maybe just plan in the flexibility to add it later.

 

We have a very handy south-facing roof with few obstructions, and I'd assumed we'd get a standard 4kWp PV install, but now I'm not sure the roof is big enough—maybe 25m² at a pinch, and I imagine an older roof might need reinforcement? So we may be looking at more like a 2kWp. That's still enough to be useful, and in fact might be cheap enough to go ahead and install it now.

 

I hear the FIT is due to expire in April, which is shame, but I'm not sure it's worth trying to rush a PV installation ahead of the other works. It shouldn't really interfere with anything else, though…

 

I'd love to include a battery but they still seem far too expensive—Energy Saving Trust says at least £4000 for 4kWh. Seems a very safe bet that prices are going to come down. But can you get smaller cheaper batteries now, say 1kWh or 500Wh for under £1000? If so I'd think about getting one of those, and adding more capacity later when it becomes affordable.

 

I was excited about solar water heating for a while, but the more I read about it, PV seems like the smarter option. Electricity is just more useful, PV sounds more reliable, and there are plenty of other ways to collect heat.

 

13 hours ago, Ferdinand said:

To my eye EWI (External Wall Insulaton)  does not look feasible without doing the whole terrace, so also wrt IWI:

6 - How high are your rooms in general?

7 - Ditto the doors? Are they original and are you keeping them?

8 - How large are your rooms (ie can you afford to lose say 100mm to insulation if you need to)? Have aerogel on your radar if you just need to insulate the front wall and your rooms are small, though your bank account will know when you have bought some.

 

I think you're right about external insulation, I haven't even bothered to look into that. None of the other terraces in the area have it (I suppose somebody always has to be first though)

 

Ceilings are about 2.9m downstairs and 2.6 upstairs. Front door 2.4m, I don't believe it's original, back doors definitely aren't.

 

The front room and master bedroom are 4.4m long so I think we could survive losing 10cm from the front.

 

The party walls won't need any insulation, is that right? Since they'll be warm on both sides.

 

13 hours ago, Ferdinand said:

In terms of where to start, I would suggest a Heat Model on the @JSHarris spreadsheet (someone needs to provide a link to where it is now), and also on the ^{Stroma EPC software}. That is to understand your house, and also to know where your target is. I would recommend aiming for at least a B on EPC, as it has to be a C for future rental if that will be needed, and is a decent place to aim for.

 

Great, I'll take a look at that. B is about what I had in mind (and it's what the current EPC says could be achieved with all the recommended measures, although I take that with a pinch of salt). Right now we're an E, borderline F.

 

13 hours ago, Ferdinand said:

If you are building a 20k-30k extension, then any extra money you spend to take your insulation from "good" to "very good" will be relatively small. ie so do it. If you sweat your extension budget just reasonably well, it should more than cover the other.

 

Will do!

 

13 hours ago, Ferdinand said:

On MVHR, you need to consider it and balance cost against benefit (including comfort), but you do need a ventilation strategy alongside your energy strategy.

 

The ventilation strategy needs to address the extra difficulty you are causing for for both moisture and air to escape from your more sealed house, compared to the original permeable-walls-full-of-holes. That is, both heat and humidity.

 

I find big benefit from a PIV at the top of the house, and some sort of outlet (eg Heat Recovery fan with backdraft shutter in kitchen or utility, and a low volume trickle setting) at the bottom (usually kitchen). It does make a material difference, either in the case of poor glazing (even single), or with well sealed 2G or 3G, as a intermediate between trickle vents (spit!) and MVHR. It is about providing an alternate route for moisture and air now that you have significantly sealed the walls.

 

Others may argue keeping the walls permeable by choice of material as they do not like full membranes. My view is still to allow the walls to be sealed more but provide robust always on background ventilation.

 

My inclination is to aim for decent airtightness, but I'm more concerned with avoiding damp, so I'll see what our architect says about how best to protect the walls and floor. He's suggesting good levels of internal insulation with a breather gap fed by small skirting vents.

 

The PIV and heat recovery extract combo sounds appealing, exactly the kind of thing I was grasping at.

 

For the heat recovery fan, is this the kind of thing you mean? https://www.envirovent.com/specifier/products/single-room-heat-recovery-unit/heatsava/ What are some good reliable brands and suppliers?

 

13 hours ago, Ferdinand said:

Finall,y remember to integrate your systems in space terms, and keep them maintainable. My last one I brought all the services above the underfloor insulation and plumbing / gas / electrics into channels in the insulation in my floating floor, which I think works. Had separate rockwool insulation under the suspended floor providing an overall insulated envelope.

 

For the next one I will look very carefully at AHSP not gas, underfloor insulation, a floating-floor type underfloor heating system, and electrics running around the edge of the room under the floating floor. That will require good underfloor insulation, and careful tactical consideration for light switches etc.

 

Interesting. That gives me lots of ideas to think about.

 

13 hours ago, Ferdinand said:

I'll stop there, but happy to answer any questions. My renovations have been mainly rentals so robustness, maintainability and resilience are very important to me.

 

Ferdinand

 

PS You need to decide how to handle those nice windows if you put 2G or 3G in if not there already.

 

Thanks again for taking the time to reply!

 

The stained glass windows I think are fake (although I haven't looked too closely to be honest). I think we can easily get something similar on the mass market, e.g. Penicuik (http://www.penicuik.com/products/decorative-options/). I got some ballpark triple glazing quotes (from http://www.ecowindowsscotland.co.uk) and they don't look too scary, so we might go for that. Eco Windows supplies Rehau "Geneo" windows, apparently some kind of hi-tech fibreglass (http://www.ecowindowsscotland.co.uk/windows/rehau-geneo-windows/). Anyone know if those are worth looking into? They're a little more pricey than uPVC but not by much.

 

It would be great to have stained glass; there are a couple of studios nearby-ish that will make new designs for us, or restore and encapsulate any vintage stained glass we might find. Definitely going to have to visit Glasgow Architectural Salvage when we get a chance!

[Iain M]

Forgot to add one more thing, re heating: I recently learned about Sunamp, and I see a lot of people on this forum are fans.

 

A Sunamp battery sounds a little pricey, but much more reasonable than an electric battery, and really tempting if it can easily deal with multiple inputs, avoid the need for a huge water tank, and give us instant hot water. Do you recommend getting one? Any sneaky downsides to watch out for?

Edited November 6, 2018 by Iain M

[Ferdinand]

 

7 hours ago, Iain M said:

The PIV and heat recovery extract combo sounds appealing, exactly the kind of thing I was grasping at.

 

For the heat recovery fan, is this the kind of thing you mean? https://www.envirovent.com/specifier/products/single-room-heat-recovery-unit/heatsava/ What are some good reliable brands and suppliers?

My standard pair are one from the Nuaire Drimaster - one of the lower models such as the Hall Control - range for the PIV and the Vent-Axia Lo Carbon Tempra  Plot the HRV, which has a basic trickle for configurable inside and a Pull Cord boost. 

 

The pair would normally cost approx £400-450 plus installation. I have been using these models since 2013, and the Tempra is not quite as silent as some would like (depends where you put it) so there may be a better alternative out there.

 

Reading your reply, I would say you need a wider knowledge on heating systems and insulation specs (what is "good"?), as the current varied ideas sound complex. If the fabric is done properly and to a decent spec a Wood Stove should be purely aesthetic, and I would point you towards considering those electric simulated wood stoves that hang on the wall.

 

Quote

My inclination is to aim for decent airtightness, but I'm more concerned with avoiding damp, so I'll see what our architect says about how best to protect the walls and floor. He's suggesting good levels of internal insulation with a breather gap fed by small skirting vents.

 

What is this? Where will it vent to? Does he mean a long, thin trickle vent?

 

And do not forget 1, or more likely 2, charge points for electric cars.

 

F

 

 

Edited November 7, 2018 by Ferdinand

[Ferdinand]

One thing you need to be obsessed by is Detail. Detail. Detail. Detail. Possibly to the extent that your architect gets bored, your wife threatens to divorce you, and your guinea pig has a brainstorm.

 

And if you aren't, other people won't be either.

 

F

Edited November 7, 2018 by Ferdinand

[Iain M]

3 hours ago, Ferdinand said:

One thing you need to be obsessed by is Detail. Detail. Detail. Detail. Possibly to the extent that your architect gets bored, your wife threatens to divorce you, and your guinea pig has a brainstorm.

 

And if you aren't, other people won't be either.

 

F

 

Yes sir! I regularly remind myself that I’m the customer and it’s my project, so hassling the architect with random questions and suggestions isn’t an inconvenience, it’s my prerogative.

[Ferdinand]

But the one guarantee you have is that some of what I say is wrong ?.

Edited November 7, 2018 by Ferdinand