Added by on 2017-05-16

Hopefully this video will help explain the difference between cold flat roof construction and warm flat roof construction, this videos show detailed drawings how a cold flat roof is constructed. I link to two other videos one on warm flat roof construction and one thats a in depth comparison between cold and warm flat roofs also showing thermal imaging of poorly performing insulated flat roofs. Animation program used was sketch up with lots of section cuts Video Rating: / 5 Related PostsThermal rehabilitation and construction of a new flat and green roofHow does efficient flat roof insulation work? Concepts from a construction site with Neoporplant adaptation, flower arrangement and vegetable container gardening on flat roofRoll Roofing , how to install a basic flat roof, torch down roofing !Waterproofing a Flat Roof with Firestone EPDM Rubber Roof MembraneGreen Roof Construction 9-30-14

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  • Doctor Doom 8 months ago

    Where is the vapor barrier installed? Beneath the plaster board or the plywood on top of the joists?

  • Daisy R 8 months ago

    What is the typical depth of a cold flat roof? I would like to do a new build extension with a flat roof but I am limited on height as there is a balcony door above where the new build will go.

  • Lake Bros Ltd 8 months ago

    Steve we are creating a cold flat roof on our extension. For the ventilation at the gutter edge we are using over fascia vents. How do we attach a trim to then use GRP or EDPM roof covering?

  • the gardener 8 months ago

    Very helpful, thank you. My flat roof joins the sloping roof of my bungalow, existing lead flashing going under the roof tiles. I dont think the existing flat roof (4 mt x 1.5 mt) is ventilated, could i ventilate each section of the roof using grills on the fascias side and front? Thank you.,

  • Craig Harrison 8 months ago

    Could I have a warm and cold roof? I like the advantage of a warm roof but I'm looking to soundproof an outbuilding. I was thinking of putting rockwool slabs between the roof joists then have an air gap then a warm roof construction on top. Please tell me what you think about this.

  • Agilast 8 months ago

    Have you tried the Agilast chopped fiberglass emulsion system? It sounds like a thinker and truly seamless system.

  • rachel ford 8 months ago

    hi, i want to construct a cold roof with a lantern in the middle. the roof is about 3800mm projection and 4800mm wide with a 2000mm x 3000mm lantern so i will have about 900mm of roof around the edge. how do i vent it from front to back if the timber upstand is there? also if i put the celetex insulation in the rafters, how does this affect putting spot lights in? will this be cold bridging?

  • Steve Roofer 8 months ago

    Do a search for round soffit vents, that will give you an idea of a event for the end of a joist, there is a certain amount of air that should be allowed for cannot remember exactly what this is as we normally use vents for flat roofs that we know come to the correct specification. Generally speaking the more ventilation you have the better all you need to do is make sure that small animals and insects cannot get through the events.

  • Jubzsta 8 months ago

    Hi, I have a flat roof which is the attached garage on my house. Half of this garage has already been converted into a utility room. I want to tear out the existing insulation and replace with Celotex. Can you advise if I need to do anything on top of replacing whats already there

  • fionah986 8 months ago

    How is the Vapour control layer fitted and is it fitted over the joists? and what type of insulation is traditionally used

  • Paul Baker 8 months ago

    Steve have you seen any houses built with only flat roofs
    Structure insulated panels would be perfect and cheaper


  • Steve Roofer 8 months ago

    Hi thanks for this info I was just out in Chicago and really wanted to work with a roofer or two for a day or so however didn't get the opportunity will be back over next May and perhaps I could see that methods you are using Speak soon

  • Steve Roofer 8 months ago

    With the cold roof vapour control is not necessary as any vapour getting past the ceiling and insulation is then removed as the space above is vented. In a hot country increase the ventilation and possibly the hight of the roof away from the insulation. Sun hits roof and roof hot, wind vents area under roof, bigger the gap between bottom of roof and top of insulation the better

  • Steve Roofer 8 months ago

    practical experience customers calling me asking for quotations or estimate are alway surprised when I start to get into details therefore I concluded that a video on warm roof cold roof construction was needed.

  • asemblance 8 months ago

    Thanks a lot for these videos, I'm an architecture graduate and have never seen the pros and cons so concisely and clearly explained! If only our lecturers would have shown this.

  • bogdan78pop 8 months ago

    Now in Chicago we do it without ventilation and instead of plaster board we use a 2" R-10 extruded polystyrene board.Make sure is airtight and has vapor barrier ,and that takes care of the thermal bridging and there will be no condensation to damage the fiber-baths.Nice and easy..!!!!! do it yourself project..!!

  • Steve Roofer 8 months ago


  • Steve Roofer 8 months ago


  • Carlos Vieira 8 months ago

    very happy to see your video,and thanks

  • w00dzys 8 months ago

    Great videos Steve. Cheers