About PENOPLEX / Insulating enclosed balconies
In this section we will cover the aspects of insulating enclosed balconies that are parts of rooms in apartment buildings. Insulating a regular enclosed balcony that is not a part of a room differs only in the thickness of the insulating layer and finishing.
1. When combining an enclosed balcony with one of the rooms (kitchen, for example), the most common question is: Do I need to insulate the walls, ceiling, and floor of my enclosed balcony? If yes, then how do I do this?
We will answer this question and a few other relevant questions below.
So, why do you need to insulate your enclosed balcony? Its standard walls, ceiling, and floor were not designed to function as part of a larger space and will not prevent heat from escaping it. When you combine an enclosed balcony with another room, its walls will no longer comply with the requirements of the old SNiP II-3-79 or the new SNiP 23-02-2003 "On Thermal Insulation of Buildings", in such a parameter as resistance to heat conductivity. In the winter, the room will be cold and the exterior wall of the enclosed balcony may form condensation and mold.
You need to insulate your enclosed balcony in order to maintain a comfortable temperature inside the room.
2. What materials do you recommend?
You will need the following tools and materials for insulating your enclosed balcony:
1. PENOPLEX® 35 extruded foamed polystyrene (the necessary thickness for a non-combined enclosed balcony is 20-40 mm, for combined 40-80 mm).
2. Drywall/Sheetrock boards (for example manufactured by KNAUF).
3. When making a cement-sand joint compound for PENOPLEX® on the floor, you will need cement, sand, and, for the dry method, particleboard, cement bonded particleboard, or water-resistant plywood.
4. Vapor insulating layer – polyethylene film with a thickness of 160–200 µm.
5. Silicon sealant.
6. Hydroinsulator (if necessary).
7. Drywall screws for securing Drywall/Sheetrock to the wall.
3. Construction technique
1. Smooth the surface of the floor to prepare it for subsequent layers.
2. If you are going to install a floor heating system that uses hot water from the heat supply system on top of PENOPLEX boards, consider using hydroinuslation. You can use hydroinsulating putties. If you are using Bitumast resin-bitumen putty you can install PENOPLEX immediately after applying it. If you are using another putty, wait before it dries (it may take from 10 hours to 2 days) or use sheet insulation (such as Isoplast or Petroflex). Leave a length of the material (50-100 mm) to overlay the walls of the enclosed balcony (see diagram).
3. Prepare PENOPLEX® boards to cover the entire area of the floor and lay them so there is no clearance between the boards and the walls. You can use putties to cover unnecessary gaps. Do not use putty between the boards of PENOPLEX®!
4. If you are going to use a layer of cement-sand joint compound, cover the gaps between PENOPLEX® sheet with adhesive (for example 3M Scotch) or cover the entire surface with polyethylene film. This is necessary to ensure that the cement compound does not leak through the gaps. If it does, it will form "cold bridges", which are undesirable. If you are covering PENOPLEX® boards with particleboard, cement bound particleboard, or plywood, you don’t need to cover the gaps.
5. Now, start working with the walls (see diagram). Prepare PENOPLEX® boards and secure them to the wall (you can use adhesives to temporary secure PENOPLEX® to the wall), cover them with polyethylene film, and then with Drywall/Sheetrock. Use anchors to secure the panels to the wall. Before you fasten them with screws, fill the holes with a silicon sealant (to ensure that the vapor insulating layer is intact).
6. When you are finished with the walls, pour a layer of joint compound of at least 40 mm, or install two layers of Drywall/Sheetrock or plywood using stagger joint technique. Fill the gaps between the walls and the floor with foamed polyethylene.
7. To secure insulation to the ceiling, use the same technique you used for the walls.
Drywall/Sheetrock
Frequently Asked Questions
1. Can I secure PENOPLEX® boards between Drywall bays?
No. Drywall bays (stud-base, in this case) will become "cold bridges". The wall may get very cold and accumulate condensed moisture. You can use platform framing for Drywall after installing PENOPLEX® boards against the wall.
Below are brief instructions: Drywall platform framing has two types of elements: KNAUF stud-bays and KNAUF joist-bays (or bays from other manufacturers). Here is the installation sequence: smooth out uneven parts of the ceiling and secure 50/40 joist-bays to it. To do this, carefully press the bays against the ceiling and at the same time press it against the layer of vapor insulation on PENOPLEX® boards on the wall. Use a rotary hammer or hammer drill to make holes in the wall (through the existing holes in the bays). Note that THE HOLES SHOULD MATCH THE ANCHORS you will be driving in them with a hammer. Then you only need to fasten the joist-bays with screws (matching the size of the anchors) to the ceiling. Clean and smoothen the floor and use a plumb line to to mark the position for the opposite joist-bay. Use your marks to secure the joist-bay to the floor using the same anchors and screws you used for the ceiling. Now you can install stud-bays. Install them vertically (use a plumb line) using joist-bays as your guide without any additional fasteners spacing them at 600 mm. For a detailed guide go to KNAUF Profiles and KNAUF Partitions at KNAUF web site.
2. Which adhesive is best for securing PENOPLEX® to concrete and attaching decorative PVC paneling to PENOPLEX® boards?
Single-component adhesives, such as KLEIBERIT PYR 501, or other similar products that do not react with polystyrene will work for working with PENOPLEX® boards.
3. Should I leave a layer of air between the paneling and PENOPLEX® when installing it inside the wall?
When installing PENOPLEX® INSIDE the wall, we don’t see why you should leave a clearance for air. In order to answer this question fully we need to know what materials you are using for each layer of your walls.
4. Can I glue PENOPLEX® boards to the wall and then glue Drywall on them using gypsum glues, such as Perlfix, etc.?
In theory yes, but in practice, you might need additional mechanical fastening. It depends on the adhesiveness the glue. To increase its adhesive effect, we recommend roughening the surface of PENOPLEX® boards.
5. What plastering should I use inside my enclosed balcony after I’ve insulated it with PENOPLEX® boards using framing? I wouldn’t want to use Sheetrock for finishing. Could you recommend specific brands and a few tips on how to use them?
After insulating your enclosed balcony with PENOPLEX® boards, we recommend specialized plastering, for example TERMOKREPS PPS OR Atlas Stopter. Clicking the links will take you to the manufacturers’ web sites with detailed information about using these plasters.
6. I’m worried about condensation on the walls of my neighbors’ enclosed balconies. I read about it on various forums. What other insulation can I use to avoid this?
Let’s find out what condensation is and how it forms. In the winter, when the difference between air temperatures inside and outside is the greatest, it creates different partial air pressures: the pressure inside is substantially higher than the pressure outside. The volume of water vapors inside per cubic meter is also greater. Vapor will try to get outside, where partial pressure is lower. When air meets a cold external wall, a brick wall, for example, its temperature drops quickly and vapor turns into droplets of water on the cold surface of the wall forming condensation. Thanks to the good vapor insulation and low vapor penetration properties of PENOPLEX®, air with a high concentration of water vapors will never reach the cold surface of the wall and of course it will never reach your neighbor’s walls, as well.
7. Where is it best to begin with PENOPLEX® boards: the walls, floor, or ceiling? How do I join the corners?
It is really up to you where to begin with PENOPLEX®. Choose what’s more convenient for you. To join the corners use the same technique as for joining insulations of the wall and floor (see diagram).
8. How do insulate window profiles? Can I just install it on the adjacent wall so the edges cover the profile, or should I mount PENOPLEX® onto the profile and join the adjacent wall with it?
If the edge of a PENOPLEX® sheet completely cover your window profile, than it is easier and better to use your first method. If it doesn’t, then use the second method.
