Penetrating Damp in Victorian House

elenapopaphoto

Doozergirl said:

You may well need the ACO drain in your french drain because of the hill, just at a lower level so it isn't breaching anything. It would be cheaper than lifting an entire patio and would get excess water away.   

Keep an eye that it doesn't get blocked, with regular maintenance.  

how does one put an ACO drain in a French drain? 

stuart45 said:

It does not look like blockwork to me. It looks more like render with Ashlar marks, which was quite common. Done with a straight edge and a bent nail to look like stonework.

if you look at the photo with the hole in it you will see it's the same material deep in the wall. it looks exactly the same material on the inside of the house, and in several other holes throughout that wall. how could it be render if it goes all the way through? (I'm not being facetious, I just don't really know very much about building materials)

stuart45

It might be stonework under the render, but if you look at the blocks they are proud of the brickwork, too big for blocks and the joints are too small for normal blockwork. Ashlar marking is a common thing on those type of houses. 
If you look at the hole the outer 20mm looks slightly different to the inner. 

Apodemus

stuart45 said:

It does not look like blockwork to me. It looks more like render with Ashlar marks, which was quite common. Done with a straight edge and a bent nail to look like stonework.

Yes, looks like Ashlar marks to me too. The section visible through the vent hole shows one of the lines externally, but with no block junction visible in the hole itself.   However, that doesn't rule out concrete blocks with cement render and Ashlar lines - I have this on the "new" bit of my house which dates to the 1940's.  What I can't get my head around is any form of concrete block construction in mass-market housing that was built before 1900.

elenapopaphoto

stuart45 said:

It might be stonework under the render, but if you look at the blocks they are proud of the brickwork, too big for blocks and the joints are too small for normal blockwork. Ashlar marking is a common thing on those type of houses. 
If you look at the hole the outer 20mm looks slightly different to the inner. 

Thank you Stuart, this is interesting and completely new to me. I will read more about it.

Apodemus

Actually, looking at the pictures again, the surface cracking that is visible on your property (but not the on the neighbour's?) does not follow block lines, which you might expect if settlement was causing very slight movement.  That would suggest to me that whatever is under there, you have quite a thick external concrete render - which again, is not so visible on your neighbour's house where the render meets the brick window surround.  While the surface cracking may also be letting water penetrate at a higher level, this is possibly less of a concern than the surface water drainage along the base of the wall. 

stuart45

Have the holes round the pipework been properly filled?

elenapopaphoto

stuart45 said:

Have the holes round the pipework been properly filled?

No actually, by the looks of it (once again bewildered by my builder, who also redid our pipework). There's also a vent thing hiding behind the soil pipe at the downstairs ceiling height, which looks like a plastic airbrick that has been installed upside down - this might be letting water in. Husband is on that today. Thank you for pointing this out! 

FreeBear

elenapopaphoto said:

Doozergirl said:

You may well need the ACO drain in your french drain because of the hill, just at a lower level so it isn't breaching anything. It would be cheaper than lifting an entire patio and would get excess water away.  

how does one put an ACO drain in a French drain?

A french drain is nothing more than a trench filled with gravel. Depending on the amount of water that might flow in, a drainage channel may be installed at the base of the trench to carry the water away (either to a soakaway or a sewer). You already have the ACO, so install it much lower and pop a layer of 20mm gravel on top. A strip of geotextile would stop small bits of stone from filling up the ACO.

Apodemus said:  What I can't get my head around is any form of concrete block construction in mass-market housing that was built before 1900.

The Victorians had been using portland cement from the 1850s. But widespread use in house construction didn't really kick off until after the WWII.

Apodemus

elenapopaphoto said:

...once again bewildered by my builder, who also redid our pipework...  

Yes, I thought his mixed use of black pipes with white bends and junctions was rather bewildering!

elenapopaphoto

Apodemus said:

Actually, looking at the pictures again, the surface cracking that is visible on your property (but not the on the neighbour's?) does not follow block lines, which you might expect if settlement was causing very slight movement.  That would suggest to me that whatever is under there, you have quite a thick external concrete render - which again, is not so visible on your neighbour's house where the render meets the brick window surround.  While the surface cracking may also be letting water penetrate at a higher level, this is possibly less of a concern than the surface water drainage along the base of the wall. 

you are completely right. we couldn't take it anymore so started hacking at the base of the wall. below is a cross section of the thick render. any chance some of that might be lime/original? the bricks look like they were pointed with lime mortar i believe?
as i suspected, there is also a huge amount of debris in the cavity wall, bridging it. 

FreeBear said:

elenapopaphoto said:

Doozergirl said:

You may well need the ACO drain in your french drain because of the hill, just at a lower level so it isn't breaching anything. It would be cheaper than lifting an entire patio and would get excess water away.  

how does one put an ACO drain in a French drain?

A french drain is nothing more than a trench filled with gravel. Depending on the amount of water that might flow in, a drainage channel may be installed at the base of the trench to carry the water away (either to a soakaway or a sewer). You already have the ACO, so install it much lower and pop a layer of 20mm gravel on top. A strip of geotextile would stop small bits of stone from filling up the ACO.

Once again thank you everyone for this very helpful discussion. We will be lowering that drain asap!!