Is it normal to have a cavity tray like this?

atrixblue.-MFR-.

I live in a Housing association rented property.


Over the course of 12 years ive lived here ive had nothing but damp patches, mold spots (green mold and black mold spores) and water destroying the plaster work in patches along the back kitchen wall, (wall faces driving rain and wind).


After many complaints, I managed to get the HA to shift their backside into gear, and they sent out Thermabead to investigate.




Now I know there is allot of snob on all the wall ties that can give issues (a previos bore scope confirmed it), ive also had extracted huge clumps of mortar mix sat ontop of the cavity tray above the patio door approx. 7-10 inches at its tallest and thickness of the cavity and approx. 20-30 inches long 3 years ago.




But what got me is I have galvanized IG box lintels sat above my doors and windows and have weep holes for drainage in the bottom of the soldier course now theres a DPC meterial improvised cavity tray that then starts another 3 brick courses up above the soldier course above IG (into inner concrete brick skin 1 mortar course above ceiling joists) this tray is completely all around the property (I'm an end house 3 bed), There were NO WEEP HOLES along the tray (HA checked archives and the architects design sheets for the house build that's has Catnik cavity trays instead of DPC improvised one and no cavity tray along the house at all catnics all covering IG box lintels above doors and windows) until 3 years ago to allow the cavity to breath and to dry out some mold and damp and what was left of fibre wool insulation that had failed and got excessively wet removed.




I'm confused as to why there is a continuous cavity tray there, as it seems pointless and meaningless in many regards especially as there was no weep holes along it (now I have them all along the tray), and it went above the IG so the weep holes for the IG were pointless as the cavity tray prevents water form going onto the IG in the first place.




Only ONE purpose I could think of is that all the ceiling floor joists are not capped off with a polythene and are open in the cavity, the cavity tray drapes over the floor joists to give them a little protection, but it has been identified that some of the floor joists will need rot treatment in next 22-32 months or so as there is a white fluffy mold all over the ends of the joist that are facing in the cavity anyway.




So what are your thoughts on having a cavity tray that goes all the way around the property and seems to serve no purpose at all other than to cause damp issues?. My uncle (a builder by trade 30+ yrs has encountered it although have seen DPC trays above catniks and IG's but all the way around a house, nor had thermabead employee's, nor did their building works and planning surveyor when I asked them).

I though trays were placed in with IG lintel boxes to help water escape, my house has none, although a DPC would make sense aboce the IG lintels Bit I thought they would be in sections above doors and windown and placed lower down than 3 courses up above first soldier course. confused dot com I am.




builders here shed any light on why?

Oh FIY and Thermabead has extracted all the snobs and clumps of house brick, clumps of mortar and what is left of old insulation (eventhough this was extracted some years ago due to making mold worse, the whole top half of the house still had it in place and it was sopping wet like a submerged sponge I could wring it out) they have knocked off and cleaned all the wall ties and water proof sealed the rear and side of the property along with putting weep hole inserts along the cavity tray and cleaned out ground floor level DPC course too. 44 massive bags of mortar, brick, snob, and old fibre wool insulation was remove altogether.
There are no catnik trays along with the IG's (they are galvanized though so no worries there).

a final bore scope confirms rot on some of the ceiling floor joists but cavity cleanly extracted nothing in there now. and have now put in their thermabead insultion (round bead balls).

Furts

I am sorry. It is too long a post for me to get my head around. But consider one snippet. Almost all houses in the 1980s were built with no weep holes to lintels. They should have been present but nobody bothered. Most lintels worked perfectly - the water went down the cavity, or it soaked through the brickwork or mortar. Particularly if the bricks were porous like LBC bricks.

I have come across your continuous tray. I am not sure why it was done. There seemed to be a phase, or fashion at one point for doing this at joist level, but those I saw like this did have weep holes.

I have also seen the same detail on timber frame houses - but your post suggests that you have a brick and block house. Perhaps you can clarify this.

As I am sure you are aware damp and mould issues in HA accommodation are invariably put down to lifestyle issues. It is the default position with HA staff, but in fairness this is usually the case. In your case it appears that there have been other technical issues.

atrixblue.-MFR-.

yes brick and block.

Furts

I am still uncertain on what your question is.

But again some snippets. It was always traditional to build joists into cavity walls These were clearly stipulated to not protrude into the cavity and were to receive two flood coats of preservative. The reality is this occurred if the work was being done with care and attention to detail. But in theory joists in cavity walls should not suffer from rot.

You are not correct in saying IG Lintels are galvanised and hence better than Catnic Lintels. It is the reverse of this. The Catnic Lintels are galvanised and then receive an epoxy powder type black coating. Hence the galvanising gets protection on Catnic Lintels but not on IG Lintels.

Regardless of the lintel manufacturer there should be a cavity tray located above the lintel.

sidefx

Furts wrote: »

I am sorry. It is too long a post for me to get my head around. But consider one snippet. Almost all houses in the 1980s were built with no weep holes to lintels. They should have been present but nobody bothered. Most lintels worked perfectly - the water went down the cavity, or it soaked through the brickwork or mortar. Particularly if the bricks were porous like LBC bricks.

I have come across your continuous tray. I am not sure why it was done. There seemed to be a phase, or fashion at one point for doing this at joist level, but those I saw like this did have weep holes.

I have also seen the same detail on timber frame houses - but your post suggests that you have a brick and block house. Perhaps you can clarify this.

As I am sure you are aware damp and mould issues in HA accommodation are invariably put down to lifestyle issues. It is the default position with HA staff, but in fairness this is usually the case. In your case it appears that there have been other technical issues.

I couldn't grasp what the OP was asking either?

But as to damp and mould issues. I live in an old house and am plagued by damp.

I leave my windows open all day every day, all year. As much as possible my washing is dried outside. When cooking I have the extractor fan on and windows open.

I am not sure what else I can do? It depresses me a lot because otherwise, it is a great house.