Hi all

Not sure where would be best as way of a Hi and introduction so I gambled on here (happy for it to be moved if needed)

Anyway, I’m a long term fan of forums having restored cars, motorcycles, renovated properties etc over the years.

The new project requires some “out of the box” thinking and looking around many of the forums it’s people quoting building regs or abusing people for not paying experts to do it for them haha...... here seems much friendlier and helpful although I know it’s not so active, so I genuinely hope others here will not only help me but also get some enjoyment out of throwing around ideas.

The project is very unique, a 400-700 yr old house (originally 2 dwellings), built against the 2000yr old city wall.
You’d think this would make it an impossible project with volumes of restrictions and lots of zeros in the costings..... thankfully not here in Portugal. There are of course some restrictions but not too many, hopefully here will be a place to hear possible solutions.

The house itself is a long thin irregular building approx 2.7m (increasing to 3.5m) x 17.5m, 2 storeys.
Originally it would of been 2 houses, each with the ground floor for animals and the upper floor for living.

Good news...
a blank canvas
Very little building regs
A fun project

Bad news...
One of the long walls is the historical wall and does have some restrictions
With the above factor suitably insulating the property or even heating is questionable
Highly unlikely to have much in the way of foundations
The opposing long wall is leaning significantly
Portugal famously suffers from sever damp issues
The lack of regs in Portugal means that everything that’s been done in the past is a joke, so literally everything needs to be redone
The other walls are of an old traditional method that involved packing any old stone or brick along with dirt (yes genuinely dirt!) 50cm thick, no damp proofing etc, with a tradional lime render.

Intention...
I’m planning to convert the house into 4 small Airbnb/holiday rentals with an overall medieval/historical theme.

I’ve lots of questions, queries and desperate pleas for help but thought the above would help paint an initial picture.

Thanks in advance and Hello again to everyone!

Thanks for the questions Peter,

Being Portugal obviously an extended summer season as a given, but being an historical tourist town it has major festivals over Easter, a couple of weeks April/May, a couple of weeks October, Xmas/NY period. It does get chilly in the latter periods and even occasional morning ground/car frost over winter.
I was advised by an expert in commercial building heating that blown air is the best option but I really am not keen on that. I did research the infrared heating panel developments but honestly I’m swayed towards underfloor heating at the moment.

Regards the 50cm wall my concern is that quite a lot of damp penetrates them currently so would appreciate advice on them..... as for small holes ouch! I’m applying to fit 6 extra windows and an extra door so yeah that’s an area I need to research also.

As for the previous works done “BROKE” would be an understatement haha I’ll post some photos soon to make you giggle and cry!

An interesting project.

Posted By: PortugalProjectI’m swayed towards underfloor heating at the moment.

Underfloor heating is normally good, but as you have damp walls you might want to lay it in a limecrete floor on granular insulation (rather than concrete) so it remains vapour-permaiable and doesn't leave the walls as the only way for moisture to escape. It would be interesting to know what the existing floor is made from.

Posted By: PortugalProjectThe opposing long wall is leaning significantly

Sounds like the advice of a structural engineer may be a good idea. On a potentially related topic, what is the local seismic risk?

Posted By: PortugalProjectI did read about a new product for flooring that is small hollow clay balls giving excellent insulation fast and easy to lay etc, BUT is in uk only that I could find.

I suppose you're thinking of Leca - https://www.leca.pt/

We used LECA and were very pleased with it. Breathable floor construction, with UFH.
Should be some posts / pictures on here, if you can’t find them let me know.

Posted By: PortugalProjectAhhh Portuguese structural engineers! €275 a very good price, the report?.... “yeah it’ll be ok, it’s stood hundreds of years and survived the giant earthquake in the 1700s”

Doesn't surprise me, and they may be right - or the next one might fell it.

Maybe you could find a UK engineer prepared to work from a plan & photos.

I'd be thinking about opportunities to reinforce the structure using the type of technique shown here - https://www.youtube.com/watch?v=tWF6Rp_NovM - formed into a framework. If the wall goes, you still have a property worth repairing. See also https://www.youtube.com/watch?v=7beGxhCLnEo (in French, and at roof level, but larger version of the same idea.)

It will be interesting to learn more about your floor investigations.

Paul (goodevans)..... a very valid point haha

I do find the more specialist a forum is the more friendly and helpful it is.... yes a generalisation.

I used Leca on my limecrete floor, but if I was doing it now I'd use recycled foamed glass.

https://www.krysteline.com/blog/foam-glass

It has better u values and it's a recycled product.

Posted By: PortugalProjectHmmm not sure why the quote isn’t working

That'll be because you used 'Text' format. If you go back and edit your post and choose 'Html' format, it will magically work, but you can't post any active URL links in a post that's formatted as 'Html'. Just a foible of the forum software.

the idea of making a truly sealed passivehaus style project seems impossible to me

Note that the 'sealed' nature of a passivhaus refers to its airtightness, not its (water) vapour tightness. I live in a very breathable passivhaus - lime and straw bales.

UK engineer

Double check legalities since we've left the EU. I can imagine you can legally use any EU engineer, but UK might be stretching it. I don't know - IANAL. Edit: Oh and FWIW I used two* engineers on my project (one straw bales, one passive slab foundation) and neither came to my site. * Actually more than two - there was another for the roof and another for the first floor, but none came to site.

Dave a very good point re air/water and one that I knew but for some reason my brain was still tieing the two together.

So I’m sure a major debate or conversation but in layman’s terms are we saying that air tightness we are restricting the airflow, were as with the breathable aspect it’s the actual materials ability to breathe?

Thanks for supporting the idea of using a ‘remote’ engineer.

For seismic events - What I did (Hungary has had some damaging events) was to get insurance for the buildings, along with fire and storm damage and then forget about it.

For heating - if you have sufficient power then perhaps a reversible ASHP so that you can advertise air/con. as well as heating as needed.

If they are small units the you can get single room MVHR units for about 250 GBP that can be installed with minimum ducting if the air/con. doesn't give a positive input ventilation by default.

I wouldn't bother with UFH, rather in the sitting areas I would put engineered wood flooring on 3cm battens with EPS between the battens (comfort issue) and tiles everywhere else (easy to clean, difficult to damage) If you go for tiles everywhere then some scatter rugs in the sitting areas.

I would insulate the lofts and put external insulation on the walls. I have a stone/rubble walled building that we used for tourist lets and we stopped doing winter, early spring and late autumn lets because it took too long to heat the building from the previous week end when we had a let that phoned on Thursday night for Friday/Saturday and it was too expensive to keep up the temp 'in case'. A reasonable level of insulation will / could make it easier to be 'always ready'. Also the insulation will help in the summer to keep a nice indoors temp.
If the building has the external walls rendered now then EWI won't (shouldn't) be an issue because EWI can be made to look like the original.

From experience I would be very nervous about asking the local builders to do anything that is even the smallest bit outside their comfort zone. (e.g.limecrete ?) Go with the local practices and methods and but first learn what they are and how to do them then watch the builders like a hawk to make sure no corners and cut. Builders everywhere are good at making the end product look OK and never mind what is under the last coat of plaster.

The French video above shows a cast in situ reinforced concrete ring beam going on. - Just the thing for your stone walls. If you need to take the roof off then put one on before the new roof is fitted. Ring beams are standard practice here even on new build.

The 2M thick city wall is either an asset or a liability. At 2M thick it is going to be very temperature stable so either put internal insulation on it or point the stone nicely and make a feature of it. For the purposes of heating I suspect it will act a bit like a floor, it will warm up in the middle to the stable room temp. and will have cold bridges at the sides.

Do you have used buildings on either end as this will affect the heating demands.

IMO structural engineers are only needed for the building authorities and for when you are going out on a limb or otherwise pushing the boundaries of the norm. The local builders have done it all before and know what works so I let them get on with it for any run of the mill stuff and only use a SE for the marginal bits. Any way there is the 'As planned' and 'As built' and they are never the same. Builders are not very good at following plans, they use the plans to get the footprint dimensions and then just build the way they always have.

The way windows are put into stone rubble walls here is that first the concrete lintels is put in above the place using support bars through the wall above to hold the wall then the wall below is removed and the sides repaired with standard bricks to the window size. If stone / rubble walls are common in the area the local builders will know that to do.

Hi again Peter

A lot of your time put into that post so my genuine thanks.

Insurance will be a definite once completed, I did speak to one agent already about insuring now who laughed and said no chance.

ASHP.... two issues, one electricity is expensive in Portugal so a factor, secondly as an historic town externally no modern items can be viewed under local law (crazy as 20m away are allowed, but not the original centre), so external ASHP units, solar panels, etc are all out of the question.

Combining the aircon/2m wall/neighbours...... in summer internally the house is very cool, even when 30deg outside its a pleasant 20deg inside, likewise in winter inside still feels a lot colder than outside. There benefits of insulating the wall are obvious but as you also suggested I’ve decided to point and make a great feature of the wall, in fact my internal layout is based all around the aesthetics of the wall feature.
Only a neighbour on one end and no benefits from that as there is a gap in between backfilled with yet more rubble and dirt.

The French video is excellent and I intend to incorporate a version of it when the roof is removed, though not wishing to Infringe on my limited internal space any further I’m still problem hunting how to do a ground floor level support.

When I originally set on this road over a year ago I intended on using local builders funded by my job.... a year later, major pay cuts, demotion, possible redundancy all covid19 related and losing faith in local builders to work outside a concrete slab floor with concrete pillar/hollow clay block wall construction method I’m definitely looking at a more hands on approach.

Thanks for the window info, it’s certainly one area I’m looking to use local builders. The thing is that in this region there is actually a deluge of work for builders so they are getting harder to find, plus they really only want large whole jobs not 2weeks - 1 month part jobs.

One showing the ‘leaning’ aspect of the wall

The previous workmanship that I’m determined needs replacing

They are all supporting the first floor