Damp control on a budget

[ormurray]

Hello, first time posting but I've been addicted to this forum since moving into an 1817 stone end terrace (FTBs). There's some knowledgeable people here! I hope they see this...

We're dealing with all the classics - damp cellar, cement render on the gable, cement pointing at the front, very old gas boiler, ground level higher than internal floor... the list goes on. We had a survey done which to be fair highlighted the issues but we loved the house so went ahead with the purchase.

We've just finished decorating the bedroom, removed some minor mould but damp looks to be under control despite external wall being timber cladded (aesthetically pleasing but its efficiacy is questionable).

We're onto the living room where I know we're amidst/on the verge of problems. Firstly it smells musty! OK the house was empty for 2 months during winter but I've noticed little improvement in the smell. Previous owner colour washed in a dark red, so of course I'm thinking what's to hide. The red paint is very easily peeling off the external wall. Is it cement plaster behind the paint? Judging by the botch jobs across the house I feel it is. I can also see tide lines in the corner next to the front door.

Unfortunately, our budget to remedy any of this is tiny. We've been quoted £10k+ to have the cement render taken off and repoint in lime which we just can't afford. I imagine making changes to floor levels is invasive and expensive too?

So - what should we prioritise before we crack on with the living room? We were going to strip the paint off (since its peeling anyway) but should we be squeezing the pot and go back to stone on this particular wall, replastering with lime?

Final note: central heating and new boiler absolutely getting sorted before autumn. If we can't afford to replaster, what's the view on placing a radiator onto the external wall to raise its temperature?

Images included for reference.
Thanks,
Olivia

 

[paulc]

So - what should we prioritise before we crack on with the living room? We were going to strip the paint off (since its peeling anyway) but should we be squeezing the pot and go back to stone on this particular wall, replastering with lime?

Final note: central heating and new boiler absolutely getting sorted before autumn. If we can't afford to replaster, what's the view on placing a radiator onto the external wall to raise its temperature?

If you go back to brick, it is well worth insulating the wall - Building regulations would require you add the stuff if you strip more than 25% of the plaster off. Wood fibre or cork boards with a skim of lime plaster would do the job.
Once you have the place well insulated and killed all the cold draughts, radiators could be hung on an internal wall. Done with a bit of forethought, you get to keep pipe runs to a minimum and avoid having to notch too many joists. Whilst on the subject, have you given any thought to a heat pump ? You may find someone like Octopus can install one at a very competitive price.

 

[larry]

Get more quotes for the rendering! We had half our house re rendered in NHL last year. Ended up with about 8 quotes until I found an old school guy who could work with Lime and wasn't going to bankrupt me. There was a story there but happy with his work .The quotes ranged from £3.5k to £11k. At the top end that wasn't even lime, a cement based monocouche. This was approx 50sq m
I did hack off as much of the old render myself though which could also help bring the price down a bit and I sorted out the scaffolding myself from a local firm.

 

[a twig]

The radiator will heat the wall so would help to dry it out, but of course that’s not great for your heating bills as all that heat will be absorbed by a damp wall rather than heating the room.

Start with the basics, check rainwater goods, gutters not overflowing, down pipes properly connected and actually taking water away

 

[larry]

Ps we are overall in a similar experience, old house and lots of problems. I've kept costs down by enthusiastic DIY and learning lots along the way. Working room by room. Have now got 4 rooms fully insulated with wood fibre, did the plastering myself (started in a cupboard to practice). Taken a lot of time to do but if you're working on a budget you can save a lot by getting handy!

 

[Lacan07]

Ps we are overall in a similar experience, old house and lots of problems. I've kept costs down by enthusiastic DIY and learning lots along the way. Working room by room. Have now got 4 rooms fully insulated with wood fibre, did the plastering myself (started in a cupboard to practice). Taken a lot of time to do but if you're working on a budget you can save a lot by getting handy!

 

[Lacan07]

If you go back to brick, it is well worth insulating the wall - Building regulations would require you add the stuff if you strip more than 25% of the plaster off. Wood fibre or cork boards with a skim of lime plaster would do the job.
Once you have the place well insulated and killed all the cold draughts, radiators could be hung on an internal wall. Done with a bit of forethought, you get to keep pipe runs to a minimum and avoid having to notch too many joists. Whilst on the subject, have you given any thought to a heat pump ? You may find someone like Octopus can install one at a very competitive price.

do you have a heat pump Paul? (apologies to the OP for the diversion)

 

[paulc]

do you have a heat pump Paul? (apologies to the OP for the diversion)

No I don't.
Was forced in to replacing my boiler last year. At the time, there was a requirement to upgrade insulation if recommended by the EPC (don't have one of those), and the grant available was only £5000. Then there was the question of where to put the water tanks inside the house. Using the airing cupboard upstairs would mean pipe runs were longer than the manufacturers recommendation.. Ended up installing a gas boiler, but the plumbing was put in with a heat pump in mind in the future. With the increase in grant and relaxation of insulation requirements, I've looked at the price of an ASHP, and Octopus are quoting me just £200 more than I paid for the gas boiler.

 

[ormurray]

Thanks everyone for the replies. Even the lower end of your quotes larry we can’t afford right now, especially if we get a new boiler. I am tempted to install a radiator there and absorb heating costs as this is at least not a large sum upfront. It’s our first house so just want to live comfortably before selling for something bigger. Maybe a heat pump in the next house!

 

[Lacan07]

No I don't.
Was forced in to replacing my boiler last year. At the time, there was a requirement to upgrade insulation if recommended by the EPC (don't have one of those), and the grant available was only £5000. Then there was the question of where to put the water tanks inside the house. Using the airing cupboard upstairs would mean pipe runs were longer than the manufacturers recommendation.. Ended up installing a gas boiler, but the plumbing was put in with a heat pump in mind in the future. With the increase in grant and relaxation of insulation requirements, I've looked at the price of an ASHP, and Octopus are quoting me just £200 more than I paid for the gas boiler.

Whats an ASHP?

Ive looked at Air to Air heating (aircon). Its a bit of a minefield, I'm not sure if its worth it. My suspicions (as yet unfounded) are they'll be very little saving for much less performance. Also, very little of it is DIY'able as there's strict rules about installation.

 

[paulc]

Whats an ASHP?

Ive looked at Air to Air heating (aircon). Its a bit of a minefield, I'm not sure if its worth it. My suspicions (as yet unfounded) are they'll be very little saving for much less performance. Also, very little of it is DIY'able as there's strict rules about installation.

ASHP - Air Source Heat Pump
GSHP - Ground Source Heat Pump
It's all a bit of a minefield with all the acronyms and abbreviations.

Installing an ASHP is no worse than any other heating source. You'd probably need to get the electrics signed off as it generally needs a dedicated spur from the consumer unit. You only need to jump through hoops and getting an MCS certified installer in if you wanted to take advantage of any government grants. Then again, if you are in a listed property or want to install the unit in an area not covered by permitted development, you'd need to put in a planning application.
Going for a GSHP would entail using a specialist as it would require some serious digging or deep hole drilling.

As for performance - Efficiency is improving, and current heat pumps should be as cheap to run as a gas boiler. Some are getting a pretty impressive COP (Coefficient of Performance) in excess of 5.0. So 5kW of heat out for every 1kW of electricity consumed. Have a look at https://heatpumpmonitor.org/ for the current tables.

 

[larry]

Sad thing is if you're not staying in the house for long it likely really doesn't pay to sort things out properly....

So definitely do the basics as above eg rainwater goods and leaks etc

Check render isn't crossing the dpc

Check outside ground levels aren't too high

Clear any underfloor ventilation (or add some)

At least the render isn't painted outside (yes?)

Definitely try and work out what internal wall is plastered with, make good with NHL based plaster, repaint with breathable paint ( have used tikkurilla optiva colour myself) and you're giving the wall at least a reasonable chance to be able to dry out.

It would not be hard or much extra work or terribly expensive to add say 60 or 80mm or wood fibre insulation also on top and you may find that helps a lot with damp control

 

[fernicarry]

I've looked at the price of an ASHP,

If you are considering a HP then the building fabric needs to perform well enough to be able to heat it comfortably with a flow temp of only 40'. Try turning your boiler flow temp down to that this winter and see how you get on. I suspect that even with a bit of insulation in your walls you'll find it less than satisfactory. You need to hit quite a high standard in terms of air tightness and U-values for a HP to be viable. And remember you'll need a whacking great hot water cylinder because they can't do DHW on demand like a combi does.

With tariffs the way they are at the moment you won't save much if anything on running costs. I think I'm about 23p for leccy and 7p for gas, so the HP would need to hit a COP of over 3 to break even. Not impossible, but at the high end of what they are typically capable of in the real world, as opposed to the fantasy land of manufacturer's specs.

 

[paulc]

If you are considering a HP then the building fabric needs to perform well enough to be able to heat it comfortably with a flow temp of only 40'. Try turning your boiler flow temp down to that this winter and see how you get on. I suspect that even with a bit of insulation in your walls you'll find it less than satisfactory. You need to hit quite a high standard in terms of air tightness and U-values for a HP to be viable. And remember you'll need a whacking great hot water cylinder because they can't do DHW on demand like a combi does.

With tariffs the way they are at the moment you won't save much if anything on running costs. I think I'm about 23p for leccy and 7p for gas, so the HP would need to hit a COP of over 3 to break even. Not impossible, but at the high end of what they are typically capable of in the real world, as opposed to the fantasy land of manufacturer's specs.

Had run with a flow temperature of 50°C last winter and was reasonably comfortable. Doing a few thermal upgrades over the summer months, so will try turning the flow temperature down even further next winter. Would probably need to fit a couple more radiators or increase the size (really don't want honking great type 33 rads though).
As for hot water, did have a gravity fed system until I replaced the boiler. Had to run taps for an age before getting hot water. A tank heated by a heat pump would be at mains pressure, so hopefully, the water would run a bit faster. The spot earmarked for a tank would give me quick delivery to the kitchen at the expense of having to wait in the bathroom.
Currently paying 4p for gas, and 20p for electricity, so would need a CoP of 5 to break even - That would be a tough target to meet on a freezing cold day. That said, there would be a saving by not paying standing charges for gas as the supply could be disconnected.

 

[fernicarry]

Where are you getting gas at 4p a unit?

Remember the power output of your radiators is proportional to the delta between the flow temp and the room temp. Say the room is 20 then a flow of 40 will develop 2/3 of the power of a flow of 50. So you’d need to decrease your heat loss by a third or increase your radiator area by a third to stand still.

This place needs flow temps of over 60 in the winter so I’m completely on a hiding to nothing when it comes to HPs.

Put in a secondary return for the DHW to your bathroom so you don’t have to wait for hot water.

 

[ormurray]

Sorry to bring the topic away from HPs however having started stripping the paint (it came clean off the bottom half of the wall) I noticed the plaster ‘springing’ away from the wall. Sounds hollow when you knock too. What layers do we have here? The layer behind the top skim is full of salts. I so desperately want to rip all this plaster off but I’m worried about the cost of next steps! With an external cement render, is there any point using lime inside?

 

[paulc]

Sorry to bring the topic away from HPs however having started stripping the paint (it came clean off the bottom half of the wall) I noticed the plaster ‘springing’ away from the wall. Sounds hollow when you knock too. What layers do we have here? The layer behind the top skim is full of salts. I so desperately want to rip all this plaster off but I’m worried about the cost of next steps! With an external cement render, is there any point using lime inside?

We should be apologising to you for wandering off with talk about heat pumps.
Nothing to gain from putting lime on top of (presumably waterproofed) cement render. So might as well use Bonding coat (to build up thickness) and Multifinish top coat to match what you already have.

Where are you getting gas at 4p a unit?

On Octopus Tracker - The downside to cheap gas & electricity is the price could rise to 100p/kWh for electricity, and 30p/kWh for gas. So far this year, the rates have been below OFGEM's SVR price cap, and I've saved some 20-30% on the bills.

 

[Jeregret23]

"Springing Plaster" - External cement render - I'm just hacking it all off to try to dry it out so the slugs stop treating me like a Travelodge! I feel I need to peel back to basics.

 

[aockenden]

What layers do we have here?

From the picture it looks like gypsum skim on top of a cement scratch-coat (typical for modern bodge-work in old houses) but the lighting in the picture could be playing tricks to the eyes.

The layer behind the top skim is full of salts. I so desperately want to rip all this plaster off but I’m worried about the cost of next steps! With an external cement render, is there any point using lime inside?

If you have the motivation and compulsion to remove it all back to the bricks I think you should. We stripped no less than 10 layers of modern crap off the inside face of our stone walls to get back to original lime-washed stone, and then redid it all using insulating lime plasters. It has definitely felt very satisfying to correct all the misunderstandings and mistakes from years of abuse of the house, though it's definitely a huge amount of work.

As to the question about if it's even worth doing in lime if there's cement render on the outside face of the walls, YES there is still big value to be had from restoring the breathability / capillarity on a single side of a solid masonry wall. That way, even if the moisture can't escape to the outside, it can evaporate off into your interior air and be ventilated out of the building. It will also provide a condensation redistribution network that buffers and de-concentrates moisture, and allows it to evaporate more quickly which will help protect from internal condensation problems.

"All or nothing" is usually a fallacy. Getting some things right and some things wrong is usually better than getting everything wrong.

 

[ormurray]

That’s a helpful response thank you aokenden