westcoast

Microcement people are coming back to sand down whole tray and re apply microcement so waterproofing is not an issue im just wondering if I should pour concrete in the hole for strength or match the screed material (sand and cement)

Annoyingly after final floors went down (microcement) we noticed shower drain rocking and subsequent cracking of microcement. turns out linear drain wasn’t seated correctly into mortar by plumber - 5mm gap under ‘wing’ of drain. Gap fixed now with epoxy. You can see I removed a lot of screed cement during my investigation: should I repair this with concrete or sand+cement? in any case I’m thinking of using some steel dowels to connect all the elements. its about 100mm deep but only 15mm deep over pipe!

Harebrained idea #43: We’re having an extremely dry September so I’m trying to dry out the roof as much as possible with dehumidifier. The plan is to block scupper drain and fill the roof with about an inch of water and add a tracing dye. Interestingly I cut some of the EPS out and found it to be dry higher up away from OSB..

Cool, I dont understand 'brought down the walls' though? We have a parapet design, so surely if should be 'brought up the parapet wall' to keep condensation moisture within - like a big basin or swimming pool?

Interesting Does Alutrix have any 'self-healing' properties similar to bituminous nail tape? Any VCL I put in is going to be riddled with screw-holes from the GRP fixings...

Apologies, I dont have photos yet, and now i've been called away to work (for 2 weeks) UPDATE: - I went up on the roof, swept and cleaned.. examined every inch of the GRP in pooling area especially along joints - no evidence of cracking or de-lamination - I spoke with our supplier, he said typically its unlikely to be a leak, but he's happy to come back and inspect His first thought was condensation and he asked what kind of building works we had recently carried out. I told him 65mm of liquid screed about 1 month ago! We vented the house for a week during the drying process, but doors and windows closed since (we have air-tightness membrane 80% installed). He advised to fully vent the house for a few weeks and monitor the situation. I have taken a 120mm hole-saw and punched out the worst of the damp OSB and exposed the wet EPS to help drying.

Thanks for this reply. you’ve helped me come to the conclusion we will have to cut open the fibreglass at some point: - Cut hole in fibreglass - Remove insulation - Cut out bad OSB - Replace with marine ply - Repair DPM - Lay some kind of bituminous product in fixing line (pro clima naideck or similar) - Replace insulation and get fibreglass people back to hopefully repair under warrantee! This will solve both possible issues. Unfortunately I won’t be able to carry out this work until next summer, so for now it means continuing the build with a damp spot🫤 I will continue to check for any pinhole leaks tomorrow.

Irish west coast! will take some pics tomorrow

Still following up on possible leak but: Although its been wet, its also been very warm and very humid at times. A LOT of variation in the weather right now. The house is unfinished, but well insulated (200mm external insulation, 150mm kooltherm under screed). Some hot days Ive open the door and been greeted with cool air from the day before Some chilly mornings i've been met a nice warm air from previous day. Is it possible condensation within insulation is the culprit?

BTW thanks everyone

Scupper drain happens there through parapet wall - exit pipe fully fibre-glassed, I dont suspect drain to be leaking because wall is bone-dry. Yes, some pooling happens around scupper drain, I will go up on roof for a look now for any problems.

Hard to tell. We had a quite a wet install so some mold was present immediately after install, after about 6 months I checked the dark area and it seemed bone-dry. Since then I've always assumed it was dry.. but maybe it was getting a little damp on-and-off. Very, very wet weather recently.

The flat roof 9x9m has quite a good fall on it all converging at this point. So my theory is all condensation will collect at this point too. the fibreglass team seemed very professional, 30 year guarantee etc..

Hi there, my warm flat roof is damp in lowest spot. roof buildup: -fibre glass -200mm eps -waterproof membrane (turned up and over insulation) -18mm OSB -Timer I-beams - VCL (pro clima intello) It’s a new build and the joists are still bare inside. Fibreglass roof +insulation has been installed for over a year. My theory is that the fibreglass installers used long fixings to fix into roof deck. This punctured the waterproof membrane (dpm) and has allowed the condensation present in the insulation to seep onto deck and collect at lowest point. Solutions!? maybe I should carefully cut this bad OSB out and stick some VCL (intello), fleece-side out to wick moisture into the house and evaporated by our ventilation? thanks, any reply’s would be very much appreciated- bit of an emergency at the moment!! J

OK interesting. I'm now trying to work out if any waterproofing measures are needed when using microcement. Microcement (resin based) is 100% waterproof ...but i'm concerned about the product cracking at interface between Sand+cement and drain