How much technical detail should a construction drawing show?

[Kelvin]

Good you have got this sorted. I’ve become a bit more sanguine about problems because there is generally always a fix. I have an ongoing disagreement with the flat roof company at the moment over the quality of their work which is just another issue in a long list I’ve had with this build. It could be worse though. I was chatting with a plasterer who built a house not far from us. His wife was taking a delivery in and the driver was getting increasingly impatient with her opening the site up. This stressed her out a bit and she fell down a hole badly breaking her ankle. The driver pissed off leaving her in the hole and she was there for 40 minutes before her husband could get to her. 

[Adsibob]

12 minutes ago, Kelvin said:

Good you have got this sorted. I’ve become a bit more sanguine about problems because there is generally always a fix.

Yes, well hopefully this is now fixed. Only time will tell. We need lots of rain to test it. But if it’s fixed this easily then it will be another example of me worrying excessively over sh!t not with worrying about. 
 

Sorry to hear about your roof.

 

15 minutes ago, Kelvin said:

The driver pissed off leaving her in the hole and she was there for 40 minutes before her husband could get to her. 

That’s terrible!

[Kelvin]

Get a hose onto it although more rain is due. 
 

Yes a bit disappointed with the flat roof. It performs as designed so there’s no leaks or anything like that. It’s more the quality of the finish detail which is poor in my opinion. Fortunately, for the most part, it’s all on the roof elements you can’t see from the ground apart from two areas. I am getting a bit tired of being told by people that not worry you won’t notice after a few weeks/months. 

[saveasteading]

3 hours ago, Adsibob said:

example of me worrying excessively over sh!t not with worrying about

Not really. It's right to question stuff, and it's good to get it either sorted or discounted.

That was worth sorting.

 

[saveasteading]

3 hours ago, Kelvin said:

being told by people that not worry you won’t notice 

How about a date on your calendar to check it annually (and maybe clean off moss and leaves, but forget the rest of the year?

[EdHat]

Weep holes are important but a lack of them doesn't often result in water ingress unless in very exposed locations.

 

Were you able to confirm there is a cavity tray when the weep holes were installed.

 

You mentioned the lintel has a integrated cavity tray. Can you get a product reference as I'm not aware of these.

Usually you have a separate cavity above the lintel. This protects the lintel and has stop ends to stop water running of the ends of the tray,

 

If you have a galvanised steel lintel, the fixings through the head of the window would have damaged the galvanising on the lintel, especially if the fixings were corroded, so it would be important to make sure the lintel is protected by an intact cavity tray.

 

 

Storm Dry has it's place but shouldn't be necessary on new work done right. I'm surprised to hear a BCO accepting it as an alternative to a cavity tray,

An issue with Storm Dry is when cracks eventually form in it through movement and deterioration of the masonry it can allow moisture in and trap it in the wall preventing it from drying out as most of the wall is still waterproof.

[Adsibob]

1 hour ago, EdHat said:

Were you able to confirm there is a cavity tray when the weep holes were installed.

My builder assures me it was installed. I went through my architect’s photos from the build, but unfortunately they don’t capture that level of detail on that particular aspect. I don’t have much choice but to trust the builder is not spinning me a yarn. 

[Adsibob]

2 hours ago, EdHat said:

You mentioned the lintel has a integrated cavity tray. Can you get a product reference as I'm not aware of these.

You will find a few on google. Here’s an example:

 

https://keyfix.com/product/non-combustible-cavity-tray-lintel/?ppc_keyword=cavity trays with lead&gad_source=1&gclid=Cj0KCQiAjMKqBhCgARIsAPDgWlx8CyNhgFmA730RIROMxpaQ2MGKnkndaf1HQZ5MjJug3wNxZHAFUg0aAgSrEALw_wcB

Edited November 13, 2023 by Adsibob

[Adsibob]

Update: some 7-8 weeks after the “fix” entre had water ingress today, after about a week’s worth of almost daily rain. It wasn’t a lot of water, around 20ml. So unfortunately, the introduction of 5 weep vents, removal of the vertical screws and filling the holes with plenty of sealant does not appear to have fixed this issue, although the amount of water getting in appears to be marginally less than before.
 

I’m pretty confused about what is causing this issue now. Here are my current ideas:

 

Possibility One:

I need to check, but I believe the coping tiles at the top of our parapet wall do not cover the entirety of the top course of bricks on the parapet wall, because they were installed to end about 5mm away from the facing edge of the brick, meaning that the entire parapet wall has a small 5mm wide strip which is exposed. My architect, who designed this, didn’t think it was an issue because bricks can be pointed with a recessed pointing, so it’s quite common for that much of a brick’s edge to be exposed.

 

Possibility two:

The coping tiles touch each other, but there must be a vulnerability at the their joints. That said, the roof membrane is laid to go up the parapet wall and over the coping tiles, or perhaps it was the other way around, but either way there is a membrane protecting the top surface of the parapet wall (other than the 5mm strip mentioned above).

 

Possibility Three

The sealant applied to the bricks could be rubbish, or it could have been inadequately applied. I have no idea what product was used as I didn’t specify it. It was just something the main contractor did of his own volition and I didn’t object because I thought it was a good idea and I was happy he was doing it. I think they were thorough in the application as I recall being concerned the white liquid was discolouring the bricks, but then felt reassured once the sealant dried and bricks returned to their original colour.

 

Possibility Four

Some issue caused by the window company having pierced the cavity tray when they screwed into the lintel from underneath. These screws were removed 8 weeks ago by my builder who told me they weren’t necessary and that the window “wasn’t going anywhere” because it’s sufficiently fixed at the sides. They filled the holes with sealant, but I guess there could still be an issue. 
 

Possibility five:

Something I’m not thinking of.

 

Any thoughts as to what to do? A RICS surveyor I spoke to about this a couple of months ago thought that to eliminate the parapet wall as the culprit I should do a hose test on the different parts of the parapet wall. But given the omission of weeps was such a bad error, we ended up focusing on that, so never hosed the parapet wall. Also tricky as to how you do such a hose test given water will trickle down from the parapet wall along the outside of the brickwork, so it does not seem to be a sufficiently specific test so as to be reliable.

[Mattg4321]

Sorry to hear about this. Do you have any pictures of the top of the parapet wall? I’m not an expert, but it sounds like trouble if what I’m imagining is accurate. 
 

Surely there should be an overhang though?

 

Parapet walls are notorious for causing problems though, that much I do know. 

[Adsibob]

Thanks @Mattg4321, it is quite concerning but I’m going to try and not panic, as it must have a solution, just need to figure out what that is.

 

The only photo I have to hand is below. You will see a think grey material at the top of the parapet wall. This is the fake slate tile we laid at the coping stone. We have no overhang, in fact we have the opposite: a small 5mm recess. In addition to the plastic fake slate tiles we have the membrane, which I will check tomorrow and photograph more closely. Then post here.  
 

[MikeSharp01]

Is there any way you can pop a tarp over the suspect area and see if that sorts it. At least then you know the area of ingress. I once had a leak in a building which was found to be travelling 5 meters horizontally from the place of ingress. 

[MikeSharp01]

Looking at pic though might make it tough.

[Mattg4321]

Not that I take too much notice and as above I’m no expert, but that seems like an unusual design and something I’ve never seen (at least noticed) before. To me it looks as though it’s missing a capping piece or coping stone etc, although it’s obviously been designed this way. 
 

Mortar isn’t waterproof so surely it’s inevitable water will find its way into the cavity. Ok, this should be dealt with, but it’s far from ideal. 
 

I’m sure someone more knowledgeable than me will be able to comment soon though 

[Mattg4321]

https://www.labcwarranty.co.uk/technical-blog/guide-to-creating-weatherproof-parapet-walls?hs_amp=true
 

This is informative to someone with only basic knowledge (me!)

[Adsibob]

53 minutes ago, Mattg4321 said:

https://www.labcwarranty.co.uk/technical-blog/guide-to-creating-weatherproof-parapet-walls?hs_amp=true
 

This is informative to someone with only basic knowledge (me!)

I agree. Unfortunately I fear this is now going to be an expensive fix. 

[Adsibob]

1 hour ago, MikeSharp01 said:

Is there any way you can pop a tarp over the suspect area and see if that sorts it. At least then you know the area of ingress. I once had a leak in a building which was found to be travelling 5 meters horizontally from the place of ingress. 

Yes, should in they be possible to do that with some clamps. What sort of tarp is 100% waterproof? Standard one from screwfix looks like it will do the job. I don’t really fancy getting on a ladder in this rain. 

[joe90]

Sorry to hear about this ongoing problem. imo you need to identify if it’s the parapet or wall/window, 1200 gauge dpc plastic draped over the parapet wall and held down then soak it all with a hose and see if it leaks. )I don’t like parapet walls) have you got a drawing of a cross section of it.?

 

what does the original builder say about it?

Edited January 1 by joe90

[MikeSharp01]

8 hours ago, Adsibob said:

Yes, should in they be possible to do that with some clamps. What sort of tarp is 100% waterproof? Standard one from screwfix looks like it will do the job. I don’t really fancy getting on a ladder in this rain. 

I would just use some of the builders plastic, you don't need it to last just to confirm what is going on. This should do it: https://www.screwfix.com/p/capital-valley-plastics-ltd-heavy-duty-polythene-sheet-clear-620ga-4m-x-3m/20738

 

 

[ETC]

Should have a plastisol coated aluminium cill under the window extending out and down the wall with a drip.

[Adsibob]

42 minutes ago, ETC said:

Should have a plastisol coated aluminium cill under the window extending out and down the wall with a drip.

Hi @ETC, the window does have an aluminium cill under it, which has been powder coated the same as the aluminium window. I will check whether it has a drip profile. But why would this be relevant in respect of water ingress that is coming into the house from above the window, given the cill is below the window?

[Adsibob]

I’m reflecting on the challenges ahead of trying to identify the source of the water ingress, and I’m wondering whether I should even try the DIY approach of temporarily clamping a DPM over the parapet wall, or whether my amateur skills will just be wasting my time on this and instead I should just throw money at the problem and get a specialist in.
 

My original thought of the right “specialist” was a RICS surveyor whom I trust, and he has helped with a few things in the past, usually relating to damp or roof leaks in much older properties, but his only piece of equipment is a basic damp probe and several engineering and surveying degrees. I think of him as a very competent RICS surveyor, but one who is somewhat limited by his business model which is that he is a one man band, who hasn’t invested in any specialist equipment really.
 

A second type of specialist would be a

building defect detection company.  If their marketing is to be believed, they can use lots of clever diagnostic equipment to quickly get to the bottom of the issue before more damage is done. For example, googling around I found various companies that can do all manner of surveys and tests using specialist equipment, for example:

 

 

I’m sure this is all expensive, but having spent a crazy amount of money on our home, several hundred K on top of the crazy sum to purchase the old version of the house, and more than enough sleepless nights, in the grand scheme of things, I’m tempted by the professional approach. That said, I’m sure the industry has its share of cowboys, and I have little idea how to avoid them. 
 

Just wondering if anybody here has experience of hiring so called “specialists”? Do I understand correctly that @saveasteading or @MikeSharp01 may have professional experience of hiring or working with such “specialists” that is relevant here?

[MikeSharp01]

@Adsibob I don't have much experience of employing professionals personally. To fix the issue on the building I spoke of, we employed an investigator from a very well known consulting firm and the multinational construction company who built the place picked up the tab. They found the leak as I described it but to this day I have no idea what it cost for them to find and fix it. 

 

Personally I like to know almost as much as the professional before I call them in, so I can spot a dud, I would do a heap of my own research so I had a good idea of what was going on before I go out for a professional. 

 

In your case because your detail has slopes you will need to cover up as far as the watershed to eliminate water running down under the cover. 

[ETC]

8 hours ago, Adsibob said:

Hi @ETC, the window does have an aluminium cill under it, which has been powder coated the same as the aluminium window. I will check whether it has a drip profile. But why would this be relevant in respect of water ingress that is coming into the house from above the window, given the cill is below the window?

Apologies - I didn’t read everything and was presuming the leak was coming in through the cill.

 

Having looked at the photographs can I presume that your window is not set back as far as the back of the brick? And if this is the case where are the DPCs at the head and jambs? A sketch through the window would help.

Edited January 2 by ETC

[joe90]

Being a DIY fanatic and the little it will cost for a bit of plastic I would wrap the parapet up and try to see if that stops the leak. If it’s not conclusive then get experts in. 🤷‍♂️ it would still help if you had a sectional drawing of that wall makeup.

Edited January 2 by joe90