Perimeter drain?

[K80]

Hello!

I have a two story solid sand stone house built in approx 1856. The house is the end terrace. By April I will have been in the house a full year.
The surveyor recommended a perimeter drain around the property and I want to start researching and saving up to look at this more seriously.

I don't have any alarming damp issues, is the good news. The house has a little condensation but I manage this with opening windows and heating, and luckily mostly the condensation sits on aluminium frame windows so the worst thing that happens is a bit of mildew which I can easily clean off. I did have a mouldy wall when I moved in due to a built in wardrobe that closed off the wall trapping moisture. I removed this and reinstalled a new built in wardrobe that doesn't block the wall but instead uses it as the walls of the inner wardrobe. I keep the doors open often and I have and will continue to monitor the wall for moisture - so far all I have noticed is that the wall is very cold. If it comes to it I was thinking a dehumidifier in the bedroom might be a good idea. It's such a small house that I had nowhere else to have a wardrobe sadly. Fingers crossed this solution works.

Externally I noticed that the lower stone bricks are a bit crumbly, and I do have paving and vegetation against the wall of the house so I think I do need to address the perimeter issue.

I wondered how do I know who to hire, and to get this job sorted properly? Some googling left me wondering if trusting a gardener and landscaper was really a good idea... I don't mind a little bit of hard work but I can't imagine myself lifting pave stones on my own so I would definitely require some hired help.

The main issue is what exactly is the solution to go for? I read in another thread the best thing to do is to dig deeper so there is a proper gap for wall to dry. The house is sort of on a hill, so it just seems like a big and daunting job that I am struggling to envisage the end result.

I've attached some photos in the hopes that it's easier to give advice. My main worry is I don't know exactly what I need - how deep to dig, how wide the trench should be, what to put in it, etc?

Happy to take closer up photos later all the way around the perimeter, just a bit cold right now!
Any thoughts, recommendations and advice would be very gratefully received and if helpful I'd be willing to document the project in order to help others. Thanks in advance!

 

[Cubist]

Hi Katie(?) and Welcome to this band of miscreants,

Lovely house you have there, congratulations. As the hillside rises at the rear of the house perimeter drainage problems will be most likely at the rear and side. Less so at the front probably as that has a good slope away from it. Before you commit to any significant works it would be wise to check for the presence of a damp course and that it is above ground level including any paving. In addition you should check that there is no pooling of water during/after heavy rain and that any existing drains are functioning properly. Perimeter drains need not be sophisticated but depending on whether the area is paved and the nature of the ground it can be a fairly heavy task - we have some 'experts' here who will be more than happy to share their input on how to construct them. First though best to make sure its a worthwhile problem needing a solution.

All the best,
Cubist

 

[K80]

Hi Katie(?) and Welcome to this band of miscreants,

Lovely house you have there, congratulations. As the hillside rises at the rear of the house perimeter drainage problems will be most likely at the rear and side. Less so at the front probably as that has a good slope away from it. Before you commit to any significant works it would be wise to check for the presence of a damp course and that it is above ground level including any paving. In addition you should check that there is no pooling of water during/after heavy rain and that any existing drains are functioning properly. Perimeter drains need not be sophisticated but depending on whether the area is paved and the nature of the ground it can be a fairly heavy task - we have some 'experts' here who will be more than happy to share their input on how to construct them. First though best to make sure its a worthwhile problem needing a solution.

All the best,
Cubist

Thank you for the warm welcome and compliments. I agree it is a lovely home! And yes my name is Katey (I spell it weirdly due to a decision made as a stubborn 14 year old), you guessed it!

You're right it is very wet round the back of the house but even with all the awful rain we have been having, I have yet to see so much of a large puddle to be honest. I wonder if the drain right underneath the kitchen window is doing a very good job indeed. I try to keep it clear but it seems like only 5 minutes and another gathering of leaves and general garden debris finds it's way back, still it seems to work. Which I suppose answers the question, the drain is doing a good job in collecting everything from that northerly side of the house.

However now that I've started thinking about this I will do a bit more closer monitoring and get some photos taken of the whole perimeter up close whilst inspecting for a damp course, but I don't believe I have one, the surveyor does not mention one. One of my worries was the sand stone crumbling, particularly at the front of the house. Upon entering my front door, sometimes I see small bits of stone where it has weathered and fell away which I find quite alarming but my knowledge to whether this is actually something to be alarmed by, is not to be relied upon.

So even though it is not really "correct" to not have a perimeter gap already in place, the theory is if there is no damage it is not actually a problem? I have a bit of a follow-the-rules-by-the-book approach in matters like this, so I've been determined to follow up all the advice I got from the surveyor but now perhaps it is not so worrisome as I thought it might be.

 

[Old School]

Nothing to add re your issue but I previously lived in that village for just over ten years and recognised your house immediately, I lived at the bottom of Vicarage
Road, lovely village and surrounding countryside. Do hope HS2 is not having too much impact so far and good luck with the house.

 

[K80]

Nothing to add re your issue but I previously lived in that village for just over ten years and recognised your house immediately, I lived at the bottom of Vicarage
Road, lovely village and surrounding countryside. Do hope HS2 is not having too much impact so far and good luck with the house.

Ah!!! Hello ex neighbour, I agree the house is a bit of a landmark of the village! Thank you for saying hello. HS2 is slightly troublesome but not too bad all things considered. I often walk down Vicarage Road.

 

[Cubist]

Hello again Katey,

Damp courses have been used for many years and the earliest, that I've seen, use slate. They became compulsory in London in 1875 and the building trade adopted the practice very rapidly. Your house pre-dates this but, given the build quality, theres a chance the builder may have included one and the technique was well known before 1875. It's worth noting that DPCs became so ubiquitous that many surveyors will not mention them unless they cannot be found or there is strong evidence of damp. Whatever material is used though any damp course would be installed two or three courses of brick or blockwork above the original ground level AND below the interior ground floor level. If your house had a damp course included when it was built, look for for a dark line in the mortar that follows the mortar line along the brick/block work. Sadly, people are often careless and thoughtless and the DPC may have been 'bridged' by later works around the perimeter of the property - new paths and patios are the main culprit for such errors. Assuming though that there is no DPC the strategy of installing an effective perimeter drainage system is a good idea and, though it can be hard work for someone it is a fairly simple process and the materials needed are not very costly. Also, these do nt have to include a gap between the walls of the house and the drainage channel. Given the slope of your plot most of the later will already be following the line of least resistance and all you may need to do is help it along in any areas where it may settle and pool near/against the house.

Regarding the chipping of the stonework at the front of the house; could you provide a couple of photos please and tell us what type of stone was used in the construction.

Cheers,
Cubist

 

[88v8]

So even though it is not really "correct" to not have a perimeter gap already in place, the theory is if there is no damage it is not actually a problem? I have a bit of a follow-the-rules-by-the-book approach in matters like this, so I've been determined to follow up all the advice I got from the surveyor but now perhaps it is not so worrisome as I thought it might be.

Lovely house, and unspoilt by the plastic window vandals... The house is nicely gardened and it would be a shame to remove the shrubbery.... sandstone does naturally erode, albeit more so if it's damp.

A perimeter gap is not obligatory. However, gravel or earth is better against the house than paving, as it allows faster drainage and the rain does not bounce up against the wall.

Which way does the front face? East facing tends to have worse stone erosion due to the action of fast thawing at sunrise.

Has there been any repointing done, if so was it done in cement, or lime?
We have an internal wall that drops flakes due to damp and cement pointing.

As regards your condensation, that is quite normal in an old house and you are dealing with it in the correct way. A dehumidifier can be very useful, we have two running 24/7.
Ours are Ebac 2650.

 

[K80]

It's worth noting that DPCs became so ubiquitous that many surveyors will not mention them unless they cannot be found or there is strong evidence of damp. Whatever material is used though any damp course would be installed two or three courses of brick or blockwork above the original ground level AND below the interior ground floor level.

This is all I could find from the surveyor:
"In view of the age of the building, it is unlikely that a DPC was installed at the time of construction. In this property it can be seen that holes have been drilled in the external walls, near ground level, indicating that a chemical damp proof course has been injected into the wall. This was frustrating to find, as chemical damp proof courses aren't suitable for solid stone walls, so it is unlikely that such works have been carried out by a reputable and responsible contractor."

Given the slope of your plot most of the later will already be following the line of least resistance and all you may need to do is help it along in any areas where it may settle and pool near/against the house.

So I just need to see where it is pooling the most? I have not yet noticed any pooling but I could be more observant on this.

Regarding the chipping of the stonework at the front of the house; could you provide a couple of photos please and tell us what type of stone was used in the construction.

I've grabbed some photos, it's not always clear exactly which brick the red sandstone has come from but I've clearly got some stone that matches the pavestone step in front of my front door that is slowly eroding in layers, which I've tried to indicate in the first photo.



Some bricks, like this one, are particularly crumbly.

 

[K80]

Lovely house, and unspoilt by the plastic window vandals... The house is nicely gardened and it would be a shame to remove the shrubbery.... sandstone does naturally erode, albeit more so if it's damp.

Yes it has aluminium frame windows, although they're actually quite old now, over 10 years ago installed as the previous owner had no records of them. I had to have a few panes fixed and the window man tried his best to fix where they're catch on their frames here and there. Still seem to work well enough, though!

Which way does the front face? East facing tends to have worse stone erosion due to the action of fast thawing at sunrise.

It faces South, so it does get a lot of sun and dries quickly. Indeed the stone often feels warm on your hands if the sun has been out.
I suppose I wonder what happens with these crumbly lower bricks? Will they just erode and completely fall out?! Can you replace them?

Has there been any repointing done, if so was it done in cement, or lime?

I actually do not know, but I do hope it is lime it certainly looks a good colour but I've got no record from previous owner about any pointing work sadly. There were some samples of stuff lying around that looked like what you use for pointing. I will re-find them and we can see if they are at least lime but it does not mean they were even ordered really. The surveyor says I have a few cracks that could do with re-pointing but I can't see many when I inspect myself

 

[K80]

Photo mega-post - I took photos all the way around the perimeter. I don't think I can see a DPC? And I am not sure I have ever seen water pooling particularly anywhere, other than on paving slabs in the middle of the path. Let me know if you spot anything that might need attention!

 

[K80]

Apologies for all the spam, hope this is okay!

 

[88v8]

It faces South, so it does get a lot of sun and dries quickly. Indeed the stone often feels warm on your hands if the sun has been out.
I suppose I wonder what happens with these crumbly lower bricks? Will they just erode and completely fall out?! Can you replace them?

Yes, but we're talking geological time here....
There's nothing in your pics that looks worrisome.

However, where the stone is damp, chip off a fragment of the pointing and see if it's lime... drop it into vinegar and if it fizzes it is.
Cement pointing can lead to rapid erosion of soft stone and brick and should be removed.