1750's farmhouse and plastering

[harkerhill]

Hi

I've decided to start decorating another room in my <strike>1950's</strike> (sorry I meant 1750's!!) brick built farm house.

Once again, it's a matter of taking out the 70's novelties and making the room more original.

So far I've taken off the 5 layers of wall paper, removed two pine units (either side of the fireplace), taken the over sized fire surround out and binned the bright red curtains

Now that I can see the plaster, I can see that it's been patched many times before with lot's of old and new layers on top - skim after skim. The exterior walls are damp (the outside is concrete render which is cracked in places).

My question is how to proceed next?.... For the internal walls can I just scrape off the loose and reskim?

For the external walls, I presume lime is going to be much better to allow the wall to breathe. Does that mean removing all of the plaster back to the brick work?

Many thanks in advance.

 

[middi]

On a 1950,s building I would tend to use the same materials for repairs with which it was originally built.

By using time tested breatheable traditional materials will not harm anything exept that they may not function the way they were intended to perform on a relatively new build, usually the substrate which they will be applied on are not of a breatheable nature as they are mainly cement based.

 

[harkerhill]

On a 1950,s building I would tend to use the same materials for repairs with which it was originally built.

By using time tested breatheable traditional materials will not harm anything exept that they may not function the way they were intended to perform on a relatively new build, usually the substrate which they will be applied on are not of a breatheable nature as they are mainly cement based.

Sorry, I meant my 1750's farm house!!!

Cheers

 

[middi]

Ah..., Well ....

In that case then any cement based materials have no place in a 1750 building

You can certainly patch up things by using lime renders and mortars, this is what you should be doing, it is of little use though to do this over cement based previous repairs. You will be defeating your objective.

 

[harkerhill]

Ah..., Well ....

In that case then any cement based materials have no place in a 1750 building

You can certainly patch up things by using lime renders and mortars, this is what you should be doing, it is of little use though to do this over cement based previous repairs. You will be defeating your objective.

So do you think it's worth hacking off all of the existing cement plaster back to the brick work - even the non contaminated plaster? And the plaster on the interior walls?

 

[middi]

In a ideal world all that cement render should be removed for the fact that it inpeds the breathability and some movement needs of the building which can increase the decay rate and so decrease the life of the building.

This is not always practical for lots of different individual reasons, the main ones being cost and disruptions.

Any repairs and patch up to be carried out should always match as closely as possible the existing composition of the bulk to which it is applied to.

If it means repairing cement based render with a similar mix then that would be the best thing to do.

It would be cheap and reasonably efficient for the short term.

 

[Nemesis]

If all exterior house walls are damp internally and all are coated in cracked cement render externally then it is highly possible that is the cause of a great deal of the damp.

Water is penetrating via the cracks and it is not able to escape into the atmosphere. It is therefore soaking into your walls.

There may be other causes. such as internal condensation and poor ventilation.

 

[middi]

Unfortunately when damp is associated with old buildings most of the time is due to bad maintenance or incorrect materials used for that all inportant maintenance.

For example:
on your brick built 1750 building, later applied cement render is not in itself damaging to the building at all, untill it cracks due to very minor settlements, water will penetrate behind the cracks and will evaporate via the quickest route usually internally, creating all sorts af mess and moulds.

Obviously the quickest way is to reseal the cracks and repair any bad patches, if they sound hollow at the tap of a hammer, with some more similar wall render. It must be accepted that it is a very remedial approach to the problem and it will go some way towards controlling the problem .

There is no substitute for a proper job other than reinstate the walls elevations as they were intended to be, which most likely was bare brick bedded on lime mortar where it it would have evaporated water at the same rate that it soaked it up and no harm done.

This breathing mechanism approach should also be carried out within the inner walls renders and lime washes used , combined with adequate vantilation , for the system to work.

The problem is that we have interfered with these buildings because of contemporary trends of likes or dislikes of certain finishes and ended up setting chain reactions which we then struggle to control at the expense of ourselves and the building

What approach you take it will be guided by your determination to get it right and the depth of you pocket.

You could treat it as a project which you may want to tackle up in stages instead of a one off major disruption.

 

[NT]

Cracked exterior cement render is a classic cause of damp problems. To enable the wall to dry out the cement needs to come off. The one caveat is its easy to damage the brickwork by removing it, so proceeed with caution and test a bit first. If you cant get the cement off without damaging bricks, stop, and only remove the bits of cement that are hollow or will knock off easily without damage. Either way either leave brickwork bare or lime finish it, certainly dont put more cement on and dont use any modern paints.


NT

 

[BMcD]

harkerhill wrote:

My question is how to proceed next?.... For the internal walls can I just scrape off the loose and reskim?

Yes. But also take out any cement/gypsum based backing plaster and loose/blown lime based backng plaster and reinstate lime based plasters.
You may find it easier to remove all the plaster back to brick as trying to patch up to whats left is more hassle than starting afresh.

harkerhill wrote:

For the external walls, I presume lime is going to be much better to allow the wall to breathe. Does that mean removing all of the plaster back to the brick work?

See Middi and Co.