Advice needed on damp proofing and plastering/insulation

[jowniofownio212]

Hello

Recently bought a 1930s 2 bed bungalow which hadn’t been lived in for about a year and had no central heating. It was very damp when we bought it and were told it has a rising damp problem. It has a tar like damp proof course from when it was built.

We have removed all the carpet and the ceiling and sand cement plaster as it’s loose so going back to brick.

The external wall is 9” solid 2 layers of brick with no cavity and rendered on the outside and suspended wood floor.

When testing for damp, the readings on the brick are random, mainly lower than 20% but some areas go up to 40% but the house has not had long to air out and ventilate

My problem is that I’m getting all sorts of different opinions on what to do. Some say injection damp proof, tank it and insulated board, some say it’s not rising damp and not to insulated walls as they need to breath so use lime and plaster straight to the brick with breathable paint?

So I’m not sure what to do in this situation? Could anyone shine any light or give their opinion on what they would do?

Thanks

 

[foxhole]

Rendered wall need to be in good order since any cracks will allow in moisture trapping it and causing damp.
What are you testing the damp with, a meter for timber?, totally useless for masonry. Only way to test wall is to drill and use a proper pressure chamber meter on it which you wont have.[no ones ever proved rising damp exists].

 

[jowniofownio212]

Rendered wall need to be in good order since any cracks will allow in moisture trapping it and causing damp.
What are you testing the damp with, a meter for timber?, totally useless for masonry. Only way to test wall is to drill and use a proper pressure chamber meter on it which you wont have.[no ones ever proved rising damp exists].

Thanks for reply. There is damage to the render in some places and cracks which will soon be rectified.

The damp tester is a digital device with 2 prongs and looks to give a percentage reading which is random through out the house. Seems some of the internal walls low down have readings up to 40 on (reading on the plaster before it was removed) and there are random areas on the other walls some low and some going up to 30%.

Not really sure what to do in the state

Looking at just following the advice of a damp specialist and pay someone to injection damp proof course and tanking inside of walls and then insulated board with 25mm of insulation

The other option as there are not massive signs of damp is to DIY injection damp proof it and use brush on tanking slurry on the inside of the walls and then just dot and dab insulated boards and normal boards for internal walls and ceiling?

Any thoughts?

 

[Notch7]

This website has some good stuff for solving damp issues.

A damp surveyor recommended products such as drybase

 

[StephenStephen]

i'm no expert, but...
I would be very wary of any 'damp specialist' advice
I would recommend buying and reading 'the Damp House' by Jonathan Hetreed
I would air, heat and dehumidify the house, then see where you're at...
Repair any obvious damage or sources of water
Check ground levels outside to make sure DPC is not compromised, and that ground water moves away from the building

I wouldn't waterproof the inside of walls unless there's a specific particular reason for it (if the room is underground, for example)

 

[foxhole]

Thanks for reply. There is damage to the render in some places and cracks which will soon be rectified.

The damp tester is a digital device with 2 prongs and looks to give a percentage reading which is random through out the house. Seems some of the internal walls low down have readings up to 40 on (reading on the plaster before it was removed) and there are random areas on the other walls some low and some going up to 30%.

Not really sure what to do in the state

Looking at just following the advice of a damp specialist and pay someone to injection damp proof course and tanking inside of walls and then insulated board with 25mm of insulation

The other option as there are not massive signs of damp is to DIY injection damp proof it and use brush on tanking slurry on the inside of the walls and then just dot and dab insulated boards and normal boards for internal walls and ceiling?

Any thoughts?

Digital damp meters are not for walls, they only read surface moisture, you need a reading from inside the brickwork.
If its not broken then doesn't need fixing, your need central heating and good ventilation, once thats in leave it till next year and see if you have any actual damp.

 

[jowniofownio212]

Thanks for all advice. Will think about airing it and heating and seeing how we get on.

With regards to insulating it as it’s solid brick external wall. Could I still use insulated boards or would that prevent the house from breathing?

Any suggestions on insulating/plastering it? Some say lime sand cement straight on the brick but this feels too old fashioned?

Thanks

 

[wwwebber]

Looking at just following the advice of a damp specialist and pay someone to injection damp proof course and tanking inside of walls and then insulated board with 25mm of insulation

Did similar myself in our previous solid walled 1880's house. We removed all internal plaster, had an injection damp proof course done, damp retardant scratch coat on the inside upto 1 meter high and then 50mm insulated plasterboard on the inside of all external walls. Result - toasty house, much cheaper to heat and no damp issues

 

[Mr Chibs]

Had same situation and house style i.e. rendered on the outside.

I made sure below the floor, the ventilation was cleared and more air vents added, so the whole ground floor was connected.

I added 50mm of kingspan to every external wall (internally) and lifted all the crappy concrete floors (they were uninsulated) replace with suspended wooden floors which have 175mm of rockwool insulation between the joists, building paper on top and wood floor on top of that.

If I'm honest it's been an epic to do, but so far no more damp/smells... anywhere and it's toasty warm, so much so, I overspec'd the radiators to make sure they would be warm enough... in reality I could have done with underspeccing them!

You need to see if the damp you have is actually the bitumen damp proof thats failed or damp is caused by bridging... i.e. a concrete floor that is too high (could be outside as well), air vent blocked etc.

I've used 'dry rods' where you drill 10mm holes into the mortar line, these seem to work quite well as you can easily DIY.

Post some pics.