Traditional or Create vented gap repair?

[Lady_Mari]

I'm not sure if I am in the right forum as altho my cottage is elderly much of the original fabric has gone & repairs made in the '70's include two modern block extensions, solid concrete floors, concrete roof tiles, concrete render painted with Sandtex & (dare I mention) upvc windows.
Needless to say, it is not a listed building.

I think I have read almost every post in an effort to find answers to my most immediate problem which is basically on the only wall left that has it's original oak timbers.
The back (North) wall had an area of blown cement render. We have removed this & uncovered some very wet oak beams, much of the wattle & daub was wet & crumbly & fell out. The render had been attached to expanded metal but this has either rusted or been eaten away - (by the lime in the mortar ?)
After a few weeks of exposure the oaks have dried out & all but two are pretty sound.
We have taken advice for repairs & have two different methods suggested, we need advice as to which option we take.
First builder said will use traditional method & remove remaining concrete render, replace rotten oak studs, fix oak laths & lime render onto these. Sounds great but expensive - between £5 - 7k. (& can't start for months)

Second builder is currently renovating cottage next door & says will also remove remaining render but batten out from existing oaks to create cavity with air vents top & bottom, with membrane, fix expanded metal to apply modern render & will be much cheaper. He says this is how all modern timber framed houses are done these days.

Cost is a serious issue for us & this wall is the only one left that has timbers, the other walls are either rendered block work or painted brick.
Can anyone here offer some advice please.
:?

 

[Craig]

There are more experienced and knowledgeable people here but the second option should also work.

 

[middi]

You may find that quite a lot of the original timberwork is still there but hidden from view.

If those beams you have found are original (ie. not reused timber ), it would indicate that the building is at least 250/300 years old.

Obviousely the building has had " modern re-vamps " where the tendency has been to cover things up and use more easily available or in the misbelief ' stronger'building materials used.

As the building is not listed the best thing you can do is to insulate between the studwork, use 9mm shuttering ply boards ( 1200 x 2400 mm) to satabilise the lateral movement, counterbatten with 50x25mm(tanalised) screwed onto the studs, breather felt on these finished with EML wire nailed on these.

Any combination of render can be used to finish
Use the cheapest option, it will probably match the rest of the render better.

 

[Lady_Mari]

Thank you so much, Craig & Middi, for your replies - I am heartened, I thought everyone on here would say get rid of the concrete & lime, lime lime!

The oldest map I have found showing our cottage so far is 1889, but we have a big shed also shown on the map which we were told by previous owners has been there for at least 200 yrs & apart from its tin roof is in amazingly good order & was known as the wash-house.

The beams in the North wall & ceiling are original & the plate is also sound, the wattle & daub infill is mostly in place except where it was wettest, but on the east gable end, either side of the inglenook, there is damp in both recesses. This wall is brick, internal concrete rendered, external Weathershield painted.
We have hacked off the concrete render above where the skirting was but the bricks & lime mortar appear to be sound & dry but there are some odd drilled holes which angle downwards (perhaps a botched attempt at damp injection ?)
We are puzzled & not sure what to do next to put it right. It could be condensation but the windows are open almost all day & last winter my feet were always cold cos of the draughts.
The damp recesses have only been noticed because we were clearing the room to put electric ufh in.
We really need to sort this so we can get some warmth in our floors. (& my feet)

 

[Moo]

" internal concrete rendered, external Weathershield painted. "

The classic recipe for damp bricks - a bit like getting out of the shower, putting on a plastic mac, and wondering why you feel so clammy.

Hack off the concrete, remove the plastic paint (Strippers of Sudbury are the people to ask about this) and then sit back and let the poor old bricks dry out.

 

[Lady_Mari]

We have hacked off the concrete render above where the skirting was but the bricks & lime mortar appear to be sound & dry but there are some odd drilled holes which angle downwards (perhaps a botched attempt at damp injection ?)
We are puzzled & not sure what to do next

Will hack off more concrete today, meanwhile, how best to resurface & damp proof & ventilate bearing in mind our solid floors?
Will ufh sort it out?
Would ordinary plastering be ok?

 

[Fizzer]

You are in exactly the same boat as us, we've exposed some internal walls, found some rotting wood and also have concrete floors.

We're not sure what to do internally either. If there are cheaper, breathable alternatives to lime I'd be v interested (haven't started looking at that in earnest yet)

 

[middi]

Where damp is the topic of conversation on this forum, one of the most distressing questions asked, and almost impossible to answer by correpondence, is the scenario:-

..." my period property has damp patch in ( x ) places, it has been the subject of extensions and rennovations for the past fifty years, it has cement render and/or cement floors and the soil level is higher that the floor level ".

Whilst there may be an exeption here and there, most of the above described homes would suffer from some sort of damp problems to a varying degree.

This is due to lack of understanding or negligence from the builder, restorer or rennovator as to how and when to use modern materials to complement and protect an old building.

Unfortunately the present exasperated owners of these properties are the victims of a destruction which started in the first half of the 20th century. Cement and plastics were responsible. The irony is that cement and plastics are exellent building materials, albeit ecological disasters.

My advise to any unfortunate owners of these properties would be to seek expert on site evaluation of the problems experienced. This may be a little expensive but well worth it if the correct, long lasting, solution to the problems is implemented.

 

[Lady_Mari]

Middi, very sound advice & I wish I could get the "experts" in, but as explained in my 1st post it depends on opinion & this is why I sought advice on this site.
We really would just like to make the place warm & sound rather than spend all our free time on excavating it but stretched all ends just to get here so needs mean getting the info & doing it ourselves.
Oh to have a life outside one day, hopefully b4 retirement.


PS. Only 6 weevils in the bath this week! Progress.

 

[Penners]

The back (North) wall had an area of blown cement render. We have removed this & uncovered some very wet oak beams, much of the wattle & daub was wet & crumbly & fell out.

It would be useful to try and pin down the exact source of the wetness in the studs. Was the damp in an area immediately under the blown render, or was it at the bottom - or indeed the top - of the studs?

If it was obviously an area around the bad render that had been caused by ingress of water through cracks in the render (significantly on the north side of the building) then letting the studs dry out and then making good along the lines suggested by Middi could be all you need to do.

 

[Lady_Mari]

To Penners enquiry,

It's difficult to be absolutely sure how the wetness got in but on the N wall there is no drip ledge (or whatever it's called) the rendered wall is flush with the brick base of the house & this has been coated with bitumen. The bitumen is quite brittle & has come away in places.
The brick base is some 3ft in depth on this side of the house as the land falls away down the hill.
Internally, the studs are exposed as is the wall plate & shows no sign of dampness.

However, the gable end fireplace wall is brick & each recess is damp in the corners. We have since removed the interior concrete render & found strange holes drilled diagonally downwards that are hollow along the second course of bricks. There are signs of old previous repairs but no real wetness. Again there is no drip ledge on the exterior of this or the South wall.

The builder is coming round tomorrow to see about lime rendering internal walls so might have more info hopefully. :?:

 

[Penners]

The back (North) wall had an area of blown cement render. We have removed this & uncovered some very wet oak beams

on the N wall there is no drip ledge.....Internally, the studs are exposed as is the wall plate & shows no sign of dampness.

I'm confused, Lady Mari!

Is the north wall the one with wet studs? Are you saying that the studs are wet but the sole plate isn't? If so, then I infer that the studs are wet above sole plate level, which tends to rule out any source of damp from below.

Or are you saying that the studs are wet on their outer surface but not on their inner?

Can you help clarify the problem with further explanation, pictures or a sketch?

 

[Lady_Mari]

I'll try to unconfuse you....

This N wall is the only wall to have any studwork left. On the inside they are dry, on the outside, when we removed the blown render, we found the sole plate & studs to be sodden at the bottom.
Since uncovering they have dried out.

I will try to take some pics but not sure how to post them on this site as don't have a web page.

 

[Lady_Mari]

Right, I have the proposal for repairs by builders currently working next door.
They would erect scaffold, strip off remaining render, cut out rotten timber & replace with softwood, screw new softwood to existing oak, pack out & cover with building paper, cover with galvanized mesh, fix lead to protect soleplate, fix bell drip to base with built in ventilation, apply render with added hydrated lime (3 coats) 1st backing coat, 2nd scratch coat, 3rd floated coat.
Ventilation to top to be decided.
Cost quoted (subj to further findings when render removed) £4,500 incl vat.

The other traditional builder would also cut out rotten wood but scribe in & peg with green oak, fix oak laths, protect soleplate with slate & render with 3 coats of lime. His costs are estimated at between £5 -7k + vat.

It has also been established that the original lime render had not been removed & that this has protected the timbers above the damp area.

Internally, on the opposite wall & gable end (fireplace wall) he proposes that we attach battens to the render removed brickwork, then he will fix softwood laths & apply 3 coats of haired lime.
He says this will prevent salts from penetrating.
He also says that the bitumen coating on the brick upstand on outside walls is a bad idea as it prevents moisture escaping & forces it inside. This work has been costed at around £1000 +vat.

Has anyone got any other thoughts about any of these works before we give the go ahead, please? :?:

 

[Nemesis]

What do they mean - render with 'added hydrated lime'... ? Do they mean in fact use cement and bung in a bit of hydrate?

If so - tell them to b*gg*er off!

The second guy sounds as though he knows what he is doing I have to say...

Can't you do some of this work yourself?

 

[Lady_Mari]

Nemesis,
Agreed that the 2nd builder know what he's doing but we can only afford to have him do the interior S & W walls & that price is with us doing the stripping & battening.

The other builder is well respected (Hartog Hutton) & as we're not listed & this N wall is the only one left with original timbers we've been advised that with air-gap modern timber frame method will work. (incl. trad builder)

Please see earlier posts above from Middi & Craig.

Meanwhile, we are spending all evenings & w/ends doing the donkey work. Haven't any experience lime rendering or cutting out & splicing in new wood so feel this best left to the pro's.

 

[Nemesis]

Why are these people adding hydrated lime? And in what quantity?

Lime work is very easy to do.

 

[Lady_Mari]

I have heard it makes the mix more 'buttery' but I have no idea whether it's a good thing or not. (I can only do cake mix myself)

Other half is already fed up with working on the house, being always broke & no hols in sight so am unlikely to convince him
"Lime work is very easy to do"

 

[Penners]

Do they mean in fact use cement and bung in a bit of hydrate?

Like Nemesis, I strongly suspect that this is what they mean .

And what a shame to repair the rotted (oak?) studs with softwood. Green oak shouldn't cost a great deal more, given that the only additional cost is the material.

 

[Lady_Mari]

Penners,
I asked why not green oak & he said they find it tends to shrink & move as it dries out.

Re adding hydrated lime, please educate me so I can go back with query.