CARDOE MARTIN’S A-Z OF BUILDING SURVEYING PODCAST
DEFECT DIAGNOSIS WITH ALEXANDRA REDMOND
Host: Welcome to the Cardoe Martin Podcast this is the A-Z of Building Surveying giving you the lowdown on the world of Building Surveying. In this episode we are going to have a chat with Alexandra Redmond, a Director at Cardoe Martin. Hi Alex, how are you?
AR: I am good thanks James how are you?
Host: (0.14) Very good thanks I’ve got an interesting chat today so first things first we’ll do a bit of a warm before we venture into this world of building surveying. Now Alex hasn’t been shown the questions in advance but if she’s listened to any of the podcast before then this won’t be much of a surprise. So Alex we’ve got a quick fire round first up, (0.33) top five favourite things about building surveying, go.
AR: First thing it’s not a desk job so you get to go out on site, you’re out and about, you’re not stuck behind a desk which is really good and secondly, your jobs based on problem solving so it’s quite a satisfying job when you can help people solve problems with their buildings. I like the fact that.
Host: It’s alright you can do three if it’s easier.
AR: Yeah, I’ll have to, I’ve drawn a blank, I obviously don’t like my job.
Host: (laughter) (1.10) What is the No. 1 thing you know now that you wish you’d knew when you started out?
AR: I suppose how much fun it would be; I probably would have tried harder and maybe pushed harder.
Host: (1.20) Okay that is a good one. No. 1 thing you get asked all the time by clients and customers?
AR: Is it going to fall down.
Host: (1.31) Okay, had that one before that is a very good one. Favourite music track, album, radio channel to listen to when either doing a survey or writing reports and what’s so special about it?
AR: I never listen to anything while I am doing a survey, never thought about doing that before, when I’m writing a report probably anything by Daft Punk.
Host: (1.51) Okay good choice. Right so we’re here today to talk about your favourite subject which is defect diagnosis why don’t you give everybody just a brief rundown of what is defect diagnosis, it sounds quite complicated but I’m guessing it’s just a posh name for what, just checking stuff out?
AR: Well, it’s kind of what it says on the tin maybe from a professional stand point, defect diagnosis is the analysis and assessment of an issue that’s experienced with a building, it’s in the context of building surveying and the analysis of any contributing factors to come up with a reason for the defect and a solution to fix it.
Host: (2.35) So it’s kind of like when we’re watching Homes under the Hammer it’s the things, you’d see under Homes under the Hammer kind of stuff going on in an abandoned house and you’d be spotting these things that’s where the defect is?
AR: Yeah, I think you’re average Homes under the Hammer house probably has quite a few more defects otherwise it wouldn’t make it onto TV but for the most part yes it’s all the sort of things that you see on Homes under the Hammer, mould, damp, cracking, big holes in things, yep.
Host: (3.02) So you’ve brought a list with you about your favourite defects and the ones you want to talk about today, what have you got for us, I think cracking’s up first isn’t it, so why don’t you tell everybody about cracking, I’ve seen cracking on the walls even where we are at the moment and a new one seems to expand and contract every winter, it looks bad, is it?
AR: It really depends on the context as part of the assessment of anything, deep cracking is a defect for most wants and purposes, the nature of the cracking you’ve just described there sounds like seasonal shrinkage which is not usually a problem that’s generally when materials expand and contract as the moisture levels rise and fall between summer and winter which means that the moisture levels in those materials obviously goes up and down and when it’s down obviously it will open up and start cracking but it’s not normally indicative of a serious issue with the building. Cracking is generally something that is noticeable in various stages and various degrees of severity so you might find a crack like you’ve just described is a shrinkage crack, people might think that’s quite alarming or quite a serious problem, most of the time it really isn’t but that doesn’t mean there isn’t an underlying defect that you can’t see underneath the crack which is a problem.
Host: (4.17) Okay so that is quite interesting so tell us a little bit about that, can I spot that myself or is this where surveyors come in?
AR: You can do some preliminary tests yourself for sure, normally if you see a small crack on a wall and it’s on a wall which is a solid outer wall for instance, so its not dry lined or it’s not a plasterboard wall, if you tap on the area around the crack and the wall sounds hollow then it means that the plaster has de-bonded from the brickwork or masonry behind and that can sometimes be indicative that there are other issues at play which you can’t see.
Host: (4.50) Okay that is really useful, shall we move on I think you’ve got some sub-categories here of cracking as well so subsidence and heave, have I said that right, is it subsidence or subsidence?
AR: No people have different ways of saying it they’ll all correct, they all mean the same thing, so subsidence is a form of ground movement where the ground loses some of its integrity so particularly in dry weather or if there is a defect to nearby below ground drains or tree roots in particular which may cause damage to the foundations of the building if they grow nearby and that sort of disturbance to the local grounds can cause subsidence where you will see cracking which generally shows as wider at the base of the crack and tapering as it goes up towards the upper levels of the building. Heave cracking is the opposite of subsidence effectively its where the ground swells so the ground absorbs a lot of moisture which can be from say a tree has been removed and that tree was historically drinking a lot of the water in the ground and now that tree isn’t doing that and the ground then retains a lot more moisture and it pushes up at the building and that creates a crack which is wider at the top of the building and tapers towards the base, so that’s the principal difference between subsidence and heave.
Host: (6.07) So which one’s worse is it subsidence worse than heave, cos one’s going up and one’s going down from what I gather from what you said?
AR: It’s much more common to have subsidence, not to say that either’s better or worse, I think because it’s more common it’s generally seen as a bit easier to fix subsidence as an issue cos it’s a lot easier to put things into the ground to stabilise it then it is to extract moisture or extract the ground itself to level any pressure under the ground level.
Host: (6.38) That is very interesting, thank you I didn’t know that. So moving onto damp, so it sounds like quite a big topic but take it away, what’s great about damp from a building surveyor’s perspective?
AR: Well there’s nothing great or not great about damp really it just is, buildings and the environment is generally designed to withstand moisture, it’s part of everyday building life and the way that buildings have been constructed over the years have been to accommodate the absorption and loss of moisture throughout the material’s performance, so historically speaking materials which hold a lot of water like lime render, soft and mortar mixes, bricks and stone have all been understood to absorb moisture and retain a certain level of dampness but in more modern times construction’s moved on quite a bit in the last 50 years or so and modern methods of construction have meant that retro fitting of buildings with different systems, different types of roof, different types of windows have affected the performance of these more historic materials which were designed to breathe and be draughty and to generally cope with moisture slightly better, obviously buildings that are built in the modern times are generally newer therefore they aren’t necessarily affected by damp in the sort of traditional sense as in things like rising dampness or defects that lead to water coming into the building but they are affected by issues by condensation where there’s a lack of ventilation or heating within the property and then there’s the myriad of root causes for why dampness might occur in a building of any age.
Host: (8.20) So coming back to Homes under the Hammer then is damp one of those things that if I was to look at my potential property that I’m buying at auction and there’s a big damp patch in the kitchen for instance and the kitchens going to be ripped out and everything, is that one of those things that I would then turn around and say I do not want to buy this house?
AR: Probably not in the issue you’ve just described there, I mean it depends on the kitchen if it’s got a flat roof above it or a roof above it the chances are that that damp patch on the ceiling has been caused by a roof leak which might be a simple job to repair.
Host: (8.56) Okay so is there any way like damp meters and water testers and things, what do you guys do to diagnose if there is a damp patch or if the whole wall is going to fall down?
AR: Well hopefully damp won’t make a wall fall down that quickly but in the course of any building survey or defect analysis involving dampness we would use various instruments, the main one being a Protimeter which is an instrument with metal prongs which records the electrostatic pressure within the wall and effectively gives you a moisture level reading so it will give you between 1% and 100% moisture levels within the wall and effectively give you an idea in terms of how bad the dampness is, so you might have 100% dampness in a wall which means that there’s obviously something quite distinctive going on, that there’s something leaking in, there’s something live happening, a water leak outside, something directly getting into the wall, or potentially you could get a much lower dampness reading which might mean there’s a smaller but longer term issue which is at play and generally once we’ve had a look at the building properly we’ll be able to assess the condition of the interior, any dampness readings and also in the context of any external observations, we would be able to assess and advise on what the root cause of the dampness, what the solution to managing or rectifying the dampness is and then whether it’s a big issue or not is really up to you.
Host: (10.26) So as a surveyor do you have kind of like a rule of thumb thing, so if I were to describe a damp patch and you were to say ah nine times out of ten or seven time out of ten that’s going to be an origin from is there a bathroom upstairs, or is there a window nearby and it hasn’t been, or it’s been rendered over or its, are there any rules of thumb that you guys follow?
AR: Yeah there’s quite a few common issues which if you spot it inside there’s a very strong chance that the issue will be what you think it is, I think the first one that comes to mind for me is if you see an outer wall with a damp patch at an upper level, say on the first floor level just below the roof line and it is a concentrated area of dampness on the plaster, the chances are that that will be a leaking hopper or section of drainage outside which has leaked onto the wall over a long period and caused dampness inside, I think that’s probably one of the key ones. A lot of the time if you see dampness around windows it’s usually indicative that maybe the seals around the window frame has failed and water’s seeping in around the frames or potentially if there is an issue at ground level where you see dampness rising up from the floor that there may be an issue with the external ground levels or the building’s original damp proof course and water might be rising up through the brickwork from the ground.
Host: (11.50) So that probably leads nicely onto the next category, which is leaks, are they, I’m kind of getting now that there one in the same thing, or are they quite different?
AR: A leak is generally a single event or an event which is one thing, so for instance if you have a missing tile on your roof that may cause a water leak into the building whereas damp can be something that is a bit more progressive and long term so rising dampness being the classic example of dampness where the water is gradually absorbed through the brickwork and considered to rise up through the bricks and then escape onto the internal plaster in low level wall finishes.
Host: (12.32) Okay that’s excellent, anything else you’d like to tell us about any of those defects before we sign off, have you got another defect you’d like to mention something special for you?
AR: I think one of the main defects I’ve been reporting on, probably in my entire career actually, is garden walls that have been built to a really bad standard which then crack and those generally seem to be the things that people don’t think about when it comes to constructing a wall, these garden walls can be 2m in height, built in a very thin single brick thickness or half a brick thick as it’s known in the industry which is about 3” or 4” and without any movement joints or any supporting piers or any stabilisation and once the wall gets to that height and is built without any great substance it can become a risk for cracking, movement and eventually failure so if anybody is maintaining or building garden walls please take heed and build them properly and nice and thick and you’ll save yourself a lot of hassle in the future.
Host: (13.33) Cos they’re not cheap things to do are they garden walls, I mean you’d think the brickie would just come along and knock it up in half an hour but it’s not the case, it can run into thousands.
AR: No, no, it can be tens of thousands of pounds depending on the size and length of the wall and where you are if you have to build it in special brickwork, if you’re in a conservation area so yeah it can be a substantial amount of money and it’s very common for people to think that it’s a very small and easy job for somebody to do properly but it’s not.
Host: (14.01) Coming back to Homes under the Hammer again so I’m sitting there, and this place just happens to be a nice Edwardian red brick former rectory say, and it’s got a nice high wall around the edge, what do I look for as a layman to understand whether a garden wall has been done well or not, are there any key signs?
AR: Check the thickness of the wall if it looks like a very thick wall, so a wall that is 9” or greater in thickness is generally a good start, look for things like piers where the wall is supported every 6m or so, that will give it some intermediate restraints and also the age of the wall, if it looks like it’s been there for 200 years and it hasn’t fallen down and it’s not cracking then that’s also quite a good basic indicator for quality.
Host: (14.45) Good advice there Alex, thank you very much. So you’ve been tuned into Cardoe Martin’s A-Z of Building Surveying Podcast, thanks for listening and you thank you very much to Alexandra Redmond for joining us today.
AR: Thank you very much James.