Saturday, 22 February 2014

Broken underground drain - fixed

An outside surface drain at the Cottage is no longer used by the kitchen (presumably that's what it is located here for - bottom right corner of this picture). The previous owners had rigged up a water-butt, in to which all the rain from the rear half of the property ran... and over spilled on to the floor and down the drain. This is really bad, because the drain goes in to a septic tank and we don't really want that backing up with rain water. So, whilst I was tending the general area I decided to see if the clay/ceramic drain surround, which was cracked, was repairable.

After a little digging (maybe 2cm) I discovered an unexpected horror - the drain pipe itself was just under the surface, and broken.

You can see that the top is completely caved in here, but worse still, a look inside the hole revealed that the drain was cracked all the way through, and the rainwater had been given ample opportunity to spill in to the surrounding soil.

I decided to dig out the drain and see where it went, and how badly it was cracked.

Unfortunately, the drain trap itself was completely smashed and useless. And the first section of pipe was cracked in multiple places. A case of being too shallow and under too much foot traffic maybe?

The way to "repair" old clay pipes is to replace them. So I set about very, very slowly cutting through the old pipe with a stone-grinding disc on an angle-grinder. A reciprocating saw and hacksaw didn't even touch it, so as much as i hate angle-grinders, it was the only way.

You can get a rubber collar which converts the diameter of old clay pipes (136mm) to new pvc (110mm). Jubillee clips and a bit of GT85 get it on smoothly and hold it secure.

A new section of PVC pipe and drain trap in place and tested using a hosepipe for leaks. No leaks, so good to fill the hole back up.

I wanted to leave it as easily accessible for future works, and protected from traffic above, so bridged over the collar and tip of the clay pipe using bricks and a concrete lintel which were excavated from the hole.

The rest of the hole was then filled with pea shingle and tamped down, making sure that the new pipe was supported underneath. Rather than being quite so shallow, the new pipe is at a depth of around 4-inches at its shallowest point.

Friday, 21 February 2014

A sea of gravel - and a surprise

The removal of the concrete path which surrounded the house is complete, which has left us with a mudbath on three sides. Becoming fairly sick of walking around with clods of earth stuck to my feet I decided to expedite the process of pea-shingling the paths. Hopefully, this will also help stop any rain splashing back up as it hits the ground from various leaky gutters and pitched roof areas.

I made a discovery whilst laying the gravel in the area above (East end, outside the Sun Room doors). A stopcock for the private water supply which comes down off the hill and feeds the houses in the area. I hadn't noticed it before because it's a ground level and pretty much buried in the garden's retaining wall.

Unfortunately, either the wall has moved slightly, or it was built by an idiot, but the stopcock is now so close to the stones that it can't be turned. I'll add it to the list of things which need looking in to - the risk being that if the stone wall shifts any more it'll pop the stopcock off and we'll have a pressurized water supply jetting in to the Sun Room. What you can't tell from the picture is that it's about twice the size of a modern stopcock.

Render removal - slugs!

Well, as if we didn't need any proof as to just how much moisture was being trapped behind the concrete render, this photo shows the extent of it. Slugs, woodlice and millipedes, all enjoying the damp conditions between brick and render.

The causes of the moisture in this wall are probably 4-fold:
- It's the kitchen wall, so internal moisture from cooking and washing will have soaked in to the wall.
- The guttering running in to the water-butt and splashing in to the wall.
- The crappy, cracked concrete path letting rain through but not back out again.
- The rain soaking in through small cracks in the concrete render itself.

What is encouraging is that, above a height of around 4-feet, the concrete render is an absolute bastard to remove. It's stuck really, really well to the bricks and there's no immediate sign of damp being trapped up high. However, as you can see from the above photo, the bottom 6-7 courses of brick are sodden.

Interestingly, there appears to be an injected damp-proof course in the third course of bricks. Proof, perhaps, that that is a waste of money.

Thursday, 20 February 2014

Removing concrete render from brickwork - trapped moisture

This post covers removing concrete render from a solid brick wall in an old building. Due to the nature of solid brick walls (rather than cavity walls), it is important that a breathable render is applied, NOT a concrete render (which doesn't breathe). 

I spent a despondent half-hour this morning with a hammer and bolster chisel attempting to remove the cement render from this wall. Not a chance. No way José. Smacking the chisel into the concrete only lead to sore hands and not a lot of progress.  So I relented and wandered down to Screwfix to pick up a £50 hammer drill. And I have to say that it is worth it's weight in gold . 

Armed with a 40 mm chisel bit the drill cuts through the concrete render with ease.  Within 30 minutes I had managed to cut away around a square metre worth of concrete to reveal the brickwork underneath .

Unfortunately it has become evident that the house has been rendered at least twice.  There is evidence underneath the concrete render of concrete patching in the mortar of the bricks,  and in some places a different colour of concrete rendering underneath the outer layer. 

Evident in a lots of places is the fact that the original brickwork, which we think dates from the pre 1880s, has been badly damaged by the various rendering and removal processes. Many of the bricks have lost their outer face completely. 

So what we are going to do - at least this is the plan at this stage - is give the bare wall a couple of months to breathe and get rid of the incredible amount of moisture which is obviously trapped in it, and then we will have to re-render the bare walls in a lime render which will also allow it to breathe, albeit a little less so.

Edit: This is by far the most popular post on our blog, so I'll add some more info. 
I used a 5.5kg Screwfix SDS drill with a 1.5 inch wide flat chisel head on a low setting. This seemed to do the least harm to the underlying bricks (many of which were already knackered). Had the underlying bricks been in good condition, to preserve them I'd have had to use a hand bolster, and it would have taken weeks and weeks.  

The 5.5kg breaker was exceptionally heavy for such a long-winded job. A lighter breaker (2-3KG) would have been easier to use.

I found it easiest to carve a horizontal line across the render, following the layer of pointing underneath. Then I could use gravity to help with the drill by coming downward from that horizontal line.

There were some stubborn bits that required a higher speed on the drill, but these resulted in damage to the old, soft bricks. Slower speeds are more forgiving.

The left-over bits of cement had to be removed slowly and methodically. I found it easiest to use a bolster chisel and lightweight hammer.

One note of caution. Get a really good dust mask. I developed a really nasty cough from very minimal expose to dust which was on my own clothes. I wore a mask during drilling. Concrete and brick dust are really nasty.

Several months after I completed the job, I can now see that building breathing. Old creosote is coming out of the bricks where a chimney is, and there's enough damp coming from within the wall that there are sporadic growths of moss in places. It was definitely good for the house to remove the concrete render.

Edit 2: After a year, there's still moisture emerging from this wall, so the key is to be patient. See updated post here.

Guttering, drainage and undermined brickwork

Potentially the most major problem we face outside the house is that there is no storm-water drainage. All of the guttering just runs to water butts, which overfill and spew on to the ground around the house whenever it rains. At a guess, we have 130sq.m of roof area draining in to 2 water butts. Madness.

Lifting the concrete from around the house reveals the damage that this has been doing to the fabric of the building. You can see here a downpipe which leads from the entire back half of the house AND the garage, and just dumps its flow on to the ground by the kitchen.


A closer look reveals that years of splashing and damp have knackered the mortar in the brickwork, and the whole wall is sodden.

As a matter of some urgency now, I'm going to jerry-rig a run of downpipe to take any further water away from this area and start to dry it out. I'm also going to start slowly, carefully removing the concrete render from the brick portion of the house to let it breathe. 

Concrete, concrete, everywhere...

The entire house was surrounded by a sea of concrete. My best guess is that it was poured around 30 years ago, and has long since cracked and buckled. Whilst that wasn't the worst looking thing in the world, it suggested that decades of rain was seeping down through the cracks and, unable to come back out through the same cracks or soak in to the clay soil, was migrating along and in to the house's walls.

So, bit by bit I've been removing all the concrete from around the house, revealing all sorts of nasties used in the shallow layer of hard-core underneath it (loads and loads of broken glass).

Last night marked a moment of occassion. I finished off the first skip-load of concrete (and topped it off with a bit of wood panelling from the hallway for good measure). You can almost hear the house breathe a sigh of relief, like an uncomfortable girdle has been removed and is being taken away.

Wednesday, 5 February 2014

Creosote problems on a chimney

Despite having opened up all the fireplaces to let the chimneys breathe, several weeks of rain have resulted in more obvious evidence of the amount of creosote which has impregnated the poor old house's walls from years of wood-burning fires.

On the eastern gable-end, there have appeared 4 patches where the creosote has seeped through the lime mortar between the bricks, eaten away whatever that hideous green coating on the wall is, and is now running down the walls.

The culprit for a lot of this damage is the woodburner in the Sitting Room, which we had condemned by a sweep when it transpired wasn't flued beyond the register plate and hadn't been cleaned in eons.

You can see on the picture below that the recent rains have been soaking up the creosote and running down the chimney like heavy tar.

Today I removed the wood burning stove and its register plate, to expose a large chimney covered in what's known as Stage 3, or Glazed, Creosote. This stuff is harder than the brick it is now glued to, and a massive fire risk. If it were to catch light it would be a case of watching the house burn down I fear. It's inches thick in places, stinks and is an absolute sod to remove.

I've been looking in to chemical treatments to remove the stuff myself before we have the chimney re-flued, but it seems that the chemicals aren't available to the public in the UK, and don't work so well in cold climates. So, we'll be looking to find a Master Sweep to come and treat the Glazed Creosote just before the stacks are rebuilt and the new flexible flues are added.

French drain complete

Over the last couple of weeks, it's been raining cats and dogs, and has been the perfect weather to be outside digging a ditch and putting in a drain.

Because of the proximity to the old walls, the very shallow foundations, the shoddy retaining wall for the raised garden, and a heavy clay soil, I decided earlier to make my French drain channel fairly shallow. I want to encourage new rainfall away from the house, but not suck the life out of the clay underneath the foundations.

So, aided by the natural slope of the garden (it slopes downhill away from us in this picture) I dug a simple channel around 8 inches deep and poured in a few barrow-loads of water at the top end to check that there was a natural flow. There was, which was enormously pleasing.

The channel was then lined with geotextile membrane, which should last between 5-10 years and keep the clay particles from clogging up the pea shingle and drainage tube which it was being wrapped around.

Then, carefully filling around the tube, folding over the membrane and covering it with between 3-4 inches of pea shingle, I gradually worked my way around the front of the house.

The finished pathway complements the house (as it should do really, since the pea shingle and the house itself came from the same quarry!) and whilst its top surface is at the same level as the concrete which we excavated, the ground it lays on slopes away from the house to the drain. The whole thing is terminated in a soakaway further down the garden.