Renovating newly purchased home to be warm

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rjdvsk

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#251447 25-Jun-2019 19:52

Hi all,

I've just taken over a late 1960's house in Hamilton and have been swiftly reminded how bloody cold NZ houses are, especially after living in Norway for the past 10 years (triple glazing, under floor heating and heat pumps are pretty standard). We're now considering what we should prioritize with regards to keeping our house warm and dry. We do have heating in the form of 2 heat pumps and natural gas heating.

First thing we need to do is fix the roof, as it's the original and the lead head nails have started to corrode, plus some of the flashing is starting to lift off. We knew this from the builders report, so no surprises there. We could do a simple re-screw and replace those lead head nails, but from looking at the roof it's pretty knackered and will need replacing sooner or later. I have two quotes with regards to replacing the roof:

one is $12,500- supply and install .40 coloursteel laid on 215 self support underlay fixed with 12x55 timber teks
the other is $21,800 - using Steel & Tube Colorsteel Endura .55g

The latter comes with a 5 year warranty (what's the consumers rights do I have around roofing? should this be covered anyway?). Though it's still quite a massive difference between the two in terms of price, I have no idea of what on average a roof should cost. The area to be replaced is approx. 140m2 - any insight would be greatly appreciated.

Also I'm considering Insulation (as the house has hardly any), a ventilation system with heat transfer and retro-fitting double glazing on some of the main windows. But I'm struggling with which order I should prioritize. My current line of thinking is:

Roof
Insulation
Ventilation system with heat transfer
Retro fitting windows with double glazing

We've set aside $36,000 for getting repairs done to the house, so obviously that roof quote of $12,500 is mighty tempting.

Any insights would be extremely helpful, thanks!

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#2264518 25-Jun-2019 20:00

I'd do the standard roof rather than endura unless you're near the ocean. A roof should last 10 - 20 years so consumer guarantees should cover you, but go with a company that will be around in 10 - 20 years if you want a warranty. When you're doing roof might be a good time to insulate, if access is poor.

Your order seems reasonable. Ceiling insulation makes a massive difference, wall and floor some difference, under floor vapor barrier can make a big difference if it's damp. You'll want a ventilation system with heat recovery, not positive pressure, and you can integrate with central heating if you like - Mitsubishi Lossnay for example. Ventilation systems don't need to be on 24/7 IMHO, mine is on 3-4 hours in the middle of the day in winter, summer it's on morning and evening when it's not so hot outside. I have fresh air from the eaves going through a very good box filter, as a roof cavity has insulation, old building paper, potentially chemicals if it's been treated for borer, rats and mice droppings, etc.

Double glazing helps a bit, though we found it didn't help sound levels, it got a bit louder actually.

Leaving heating on most of the time doesn't cost all that much more in a well insulated house. Middle of winter we have it on 21 degrees 5am - 8am, down to 18 during the day when we're out, back to 21 a couple of hours before we get home, and 18 overnight - sometimes off overnight if it's not so cold. It takes days to fully heat the house through, including floors, walls, furniture, etc, if you just heat when you get home it'll never feel as warm as if heating is running all the time. Best guess is it costs about 25% more in power for us than turning it off, in a well insulated very old house.

SATTV

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#2264527 25-Jun-2019 20:22

We have a 1966 house in Auckland but I grew up in Hamilton.

From my experence, get the roof done first, while the roof is off do the roof insulation, get the best you can afford, dont skimp, just because the spec is 2.9 go for more.

Also while the roof is off they should renew the building paper.

We live in high wind zone and had no floor insulation, we put in expol, that made zero difference warm wise, but did stop dust coming out of the cracks when there was a gust of wind.

Insulation alone is no good, you need good heating, I find heatpumps useless, a good gas heater is great, make sure it is vented outside otherwise you will have condensation galore.

We put in double glazing in, we replaced rotten wooden joinery with PVC double glazing and that has made the biggest for us.

John

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antoniosk

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#2264567 25-Jun-2019 20:47

rjdvsk:

Hi all,

I've just taken over a late 1960's house in Hamilton and have been swiftly reminded how bloody cold NZ houses are, especially after living in Norway for the past 10 years (triple glazing, under floor heating and heat pumps are pretty standard). We're now considering what we should prioritize with regards to keeping our house warm and dry. We do have heating in the form of 2 heat pumps and natural gas heating.

Also I'm considering Insulation (as the house has hardly any), a ventilation system with heat transfer and retro-fitting double glazing on some of the main windows. But I'm struggling with which order I should prioritize. My current line of thinking is:

Roof
Insulation
Ventilation system with heat transfer
Retro fitting windows with double glazing

We've set aside $36,000 for getting repairs done to the house, so obviously that roof quote of $12,500 is mighty tempting.

Any insights would be extremely helpful, thanks!

5. Check for windows and how they close, and gaps between the sashes and the frames. Else you're getting natural ventilation anyway :-)
6. If double glazing gets too much, replace 3mm windows with 4mm, get the putty replaced and paint both sides of the glass. its more hassle but you really notice it when glass is thin and the paint/putty has failed
7. Carpets. It may not be trendy but wooden floorboards only in NZ seems crazy unless youre north of Auckland. Where we put carpet in, as well as thermal drapes... it does keep the heat in and will make a difference.

Ventilation systems (I'm guessing HRV) sound promising but do rely on having the warm air to replace in first place. You say natural gas heating, I'm guessing this is gas heaters with eye connections rather than underfloor central heating?

________

Antoniosk

Aredwood

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#2264568 25-Jun-2019 20:48

Roof.

Insulation.

Double glazing.

Heating. (placed here because you already have heatpumps).

And only then, consider ventilation.

Your house likely already has plenty of air leaks already. And my (albeit limited) experience of the Waikato is that the air is always really humid outside during winter. So not much that a ventilation system could do to reduce indoor moisture. Meaning to reduce indoor humidity, you need to keep the average indoor air temp higher than outside. And use aircon during summer.

There would also be times in the shoulder seasons (Autumn and Spring). Where a dehumidifier would actually be the best option. 18deg or so outside at 90+% humidity. Bringing that damp air inside won't do anything to reduce indoor humidity. While it is not cold enough for any decent amount of heating. And not hot enough for aircon.

rjdvsk

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#2264664 25-Jun-2019 21:27

What a wealth amount of information, thanks all!

The gas heating is a system I've not seen before. It sits in the floor and has a pilot light constantly going. It's called 'The Totton' by Hamilton Sheet Metal Services, though I can't find any information about it online. It's a beast of a thing though and gets the lounge bloody warm in about 5 minutes.

The windows for sure have gaps and get a crazy amount of condensation every morning. Got one of those window vacuum things which cleans it right off, though I'd rather not have to do that every morning.

It's starting to sound like I should

Go with the standard roof
Insulate
Double glaze what I can afford

See how the house (and the bank) is after all those adjustments and maybe then consider ventilation if required.

I have a couple of guys coming over the next week to give me a consultation about insulation, glazing and ventilation on the house. But I just want to gather some unbiased views before I walk into those :)

cheers!

timmmay

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#2264668 25-Jun-2019 21:35

Products of combustion of gas is carbon dioxide and water, neither of which you want in your house. If you have unflued gas heating you really need good ventilation.

froob

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#2264672 25-Jun-2019 21:54

If you have an unflued gas heater, I would put replacing it fairly high on the list.

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Aredwood

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#2264673 25-Jun-2019 21:57

Your windows most likely have condensation, solely due to the temp difference between the glass surface and the indoor air temp.

Try leaving the curtains open, and run a fan to create air movement in the lounge while the heating is going. You will most likely have far less condensation on the windows. Only because the glass surface is now warmer. Even though you haven't changed the amount of ventilation.

If you only run your heating in the evenings, then turn it off before going to sleep. Then lots of condensation on the windows is to be expected. As warm air can hold more moisture. Then as the air and the room cools down, the coldest part will be the windows. So most of the moisture is forced to condense out on the windows.

Double glazing means that the glass surface is now warmer due to better insulating properties. So less condensation on the glass.

A kludge would be to open all of the windows to rapidly cool down the house after turning off the heating, Then close the windows again once the house is cold. Simple HRV type ventilation systems actually help in this type of situation. But of course, the best situation long term is to keep the house constantly heated.

Also, when you get to the stage of replacing your windows with Double Glazed units. Consider if you actually need all of the windows that are in your house. It might be better to remove some of them and just wall over the holes. Especially if the interior is in need of repainting. As a good double glazed window has similar insulating properties to an uninsulated wall.

The 2 corner bedrooms in my house have South facing windows. (no sun whatsoever from those windows in winter) No view from those windows (but the neighbours can look inside my house through them). And those rooms also have other windows, So even with the South windows removed, They will still comply with the building code in relation to min window size. The upstairs bathroom also has way too many windows as well.

rjdvsk

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#2264676 25-Jun-2019 22:02

froob: If you have an unflued gas heater, I would put replacing it fairly high on the list.

Whew, which I'm guessing is what this system is... as far as I know it runs off a main line supply, not bottles. Complete novice here, but what are the downsides of a system like this? Moisture, safety? I can get a photo of it. My guess it's something of an antiquated system which should probably be replaced?

Aredwood

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#2264678 25-Jun-2019 22:06

@rjdvsk Post some pictures of your gas heater in the lounge and the underfloor part. As it might actually be a flued gas heater. But it might also be unflued. There are at least 2 different types which are both large underfloor units. (Im a Plumber / Gasfitter).

If unflued then as well as the moisture issue. There is also the risk of a burner fault causing the heater to produce lots of Carbon Monoxide. Therefore yearly servicing is extremely important with unflued gas heaters to catch any burner faults.

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#2264682 25-Jun-2019 22:19

I'm not sure about piped gas but bottled gas heating is very expensive to run (so I heard), same with pellet fire apparently. But don't take my word I have neither, but have 7 heat pumps once for each area/room. Our 70s house has natural ventilation lol.

bfginger

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#2264704 26-Jun-2019 00:19

Be careful of roofers. There are many cowboys in that field.

Go for no less than R4 insulation in the ceiling and R1.9 under the floor. You can go for more but the law of diminishing returns comes in. If the underfloor cavity is enclosed make sure there is a vapour barrier on the ground.

There are dry blow in insulation products to put into the walls assuming they're uninsulated but if it has original electrical wiring that may need to be replaced first. Some 1960s era insulation products may have asbestos in them but insulation was rare then.

Retrofitting double glazing into 1960s New Zealand joinery? The windows from that decade were often terrible and may be rotting and leaking by now. To replace all the joinery with something good could cost nearly $36,000. Good low e glass like XCel or LightBridge is critical. Aluminium frames should be thermally broken.

There are retrofit window films you can have stuck on the original glass which almost makes it perform like basic double glazing at a fraction of the price of retrofitting. They can reduce heat entry so they may be more suitable for the southern side. The lack of seals is a big heat loser for those old windows so retrofitting those makes a big difference. Ideally it's better to replace especially with Hamilton being Hamilton and old wooden windows aren't very secure.

As he said, a good thick carpet underlay over an old wooden floor does help. Go for woollen carpets as they're much warmer.

Never use an unflued gas heater indoors. They're unsafe and any heating benefit is undone by litres of water vapour.

Even with single glazing severe condensation is only going to happen if relative humidity indoors is too high. It shouldn't be allowed much over 60% but I'd bet it's at 75%

Handle9

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#2264708 26-Jun-2019 01:44

Is this a forever house or a step along the journey? It makes a big difference as you can pay for a lot of heating for the cost of double glazing.

I would do the roof with normal colour steel and max out the ceiling insulation. If you ever plan on going into the ceiling yourself use polyester or wool, not fibreglass. Your elbows and knees will thank you for it.

Use polyester under the floor with a vapour barrier. Polystyrene has a nasty habit of falling out occasionally if the house moves a lot.

Once I’d done that I’d want to go through a winter. If you have to pay an extra $1000 a year to heat the house but can defer or avoid 20k-30k of improvements that is a very good ROI.

If the gas heating is unflued replace it - unflued gas heaters are the devil. If it is flued and on town gas then you are probably sweet for heating, maybe use electrical heaters for spot heating in bedrooms if required.

You are very unlikely to get a payback on double glazing when you sell. It may help you sell faster but it probably won’t help you get a proportionally better sale price. Similarly for heat pumps all through the house.

If you are realistically going to stay there for 15 years then the life style benefits are there to do double glazing and more heat pumps if you want. Double glazing would definitely be the last thing I would do though.

Aredwood

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#2264709 26-Jun-2019 03:01

Batman:
I'm not sure about piped gas but bottled gas heating is very expensive to run (so I heard), same with pellet fire apparently. But don't take my word I have neither, but have 7 heat pumps once for each area/room. Our 70s house has natural ventilation lol.

It depends on what other form of heating you are comparing to bottled gas (LPG) heating. And whether you are getting the LPG from 9KG cylinders from those swap cages outside Bunnings etc. Vs from 45KG twinpack cylinders.

rp1790

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#2264749 26-Jun-2019 08:07

Instead of double glazing I'd recommend having a good look at a quality thermal film for your windows. I installed it in my lounge, dining area and kitchen (open plan) and it made a noticeable difference at a small fraction of the cost of the cheapest double glazing..

I used these guys https://www.glasshield.co.nz/

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