Garage/Workshop conversion
Garage-workshop conversion
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HOME PAGEPHASE 1. Back door removal & window replacement. PHASE 2. Construction of a stud framework supporting eight joists. PHASE 3. Plasterboard ceiling construction. PHASE 4. Partition construction with relocated door. PHASE 5 Construction of mezzanine floor.

PHASE 6. Installation of wall insulation & OSB sheathing.
(This page)

PHASE 7. Electrical re-wiring.
Garage/Workshop conversion
Garage/workshop conversion
FITTING OUT PROJECTS WOOD-TURNING
PROJECTS
APPENDIX 1. Measurements & materials.

Phase 6. Installing Wall Insulation & OSB Wall Sheathing.


Synopsis of Work for Installing Wall Insulation & OSB Wall Sheathing.
Work on all aspects was carried out in parallel.


Details of Wall Insulation.

Why Insulate?
If the intention is to spend considerable time in the workshop during the winter months and be reasonably comfortable and warm, then insulation of walls & ceiling is, in my view, essential. With insulation in place, I have found that using a small oil-filled electric radiator, it is easy to maintain a working temperature in excess of 20o C. Conversely, in the heat of the summer, the workshop keeps comfortably cool at a temperature of 18o C.

Details
I decided to use Celotex foil faced insulation board, 40mm thick for the stud walls (to fit between the 45mm thick stud timbers), and 50mm thick for the partition wall (to fit between the 70mm thick stud timbers). However, I found that obtaining board of the desired thicknesses was not easy! B & Q and Wickes both stock Celotex but not of the thicknesses that I required, and they will not order the desired thicknesses either which I think is very poor service!

I then tried ordering online from Travis Perkins where the desired thicknesses were listed as being available on their website. However, I then received a phone call to say that that although listed as available, the boards of the required thicknesses were not stocked, and likewise unavailable.

Eventually I found a company called Insulation Giant where the required boards were listed on their website, confirmed as available and delivered after a few days at a reasonable price. Can recommend them.

Insulation board delivered, 28th August 2015.

Delivery, 28th August 2015
The four Celotex insulation boards (1200mm x 2400mm x 40mm), delivered on the 28th August 2015.

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Marking out & cutting insulation board to size, 30th August 2015.

Marking Out & Cutting, 30th August 2015
The boards were easily marked using a pencil and straight-edge to rule the lines. They were easily cut using a fine toothed insulation board saw, as shown here. The edges of the boards can also be easily sanded to fit a given space using a sanding block and coarse (40 grit) sand-paper. Remember to wear a face-mask when sanding the boards as the fine dust from the sanding should not be inhaled!

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The first insulation board pressed into place, 30th August 2015.

Fitting the First Board, 30th August 2015
After cutting out with the saw and sanding to an exact fit, the first board was pressed into place.

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One Wall Completed, 1st September 2015.

One Wall Completed, 1st September 2015.
One wall finished! This was using 40mm thick insulation board.

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Partition insulation completed, 3rd September 2015.

Partition Insulation Completed, 3rd September 2015.
This was insulated using 50mm thick Celotex insulation board.

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After cutting & fitting the insulation boards between the studs, foil insulation tape was used for sealing the joints between the studs and foil-faced insulation boards. This prevents air leakage, completes the vapour control layer and maximises thermal performance. A polythene vapour barrier was stapled to the studs before the OSB boards were screwed in position on top.


Installing a Vapour Control Layer.
This is used to prevent the passage of water or moisture from within the workshop to the timber frame. People and their associated activities within the workshop will produce water vapour which, if unmanaged, can condense within or between building elements; a process referred to as interstitial condensation. This condensation can have serious detrimental effects upon the building fabric, such as causing the decay of the timber framework and corrosion of the metal fastenings, and it may also reduce the thermal effectiveness of the insulating materials. A Vapour Control Layer provides a means of protecting the warm side of the thermal insulation incorporated in a building by creating a barrier to the movement of warm, moist air.

Tools & materials for completing the insulation, September 2015.

Tools & Materials, September 2015
A roll of vapour barrier polythene, foil insulation tape (50mm x 45m), craft knife, staple gun with staples (for stapling the vapour barrier polythene to the wooden studs).

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Work in progress completing the insulation, 6th September 2015.

Work in Progress, 6th September 2015
The edges of the insulation boards have been sealed with foil insulation tape and the polythene vapour barrier is being stapled in position to the wooden studs.

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Insulation completed.

Insulation Completed, 6th September 2015
The insulation for the wall in the photograph has been completed with the insulation boards in place, edges sealed with foil tape, and green vapour barrier polythene stapled over the top. The next step for this wall will be to sheath it with the OSB boards.

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Sheathing with OSB completed, September 2015.

Sheathing Completed, 12th September 2015
The same wall after sheathing with the 18mm thick Orientated Strand Board.

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Details of OSB Wall Sheathing.

Oriented Strand Board (OSB), also known as Sterling Board, Sterling OSB, Aspenite, and Smartply in British English, is an engineered wood particle board formed by adding adhesives and then compressing layers of wood strands (flakes) in specific orientations. OSB may have a rough and variegated surface with the individual strips of around 25mm × 150mm (1" × 6"), lying unevenly across each other and comes in a variety of types and thicknesses.

Reasons for Use.
OSB is a mechanically strong sheathing which has a uniform consistency. It is a very effective substrate for the attachment of a variety of fittings such as shelves, electrical conduit and associated metal-clad sockets. The 18mm thickness OSB was preferred for mechanical strength and for accepting fixtures. OSB3 is a precision-engineered structural board for use in load-bearing humid conditions and is specifically recommended for wall sheathing, hence its use in this project. OSB is a much cheaper option than using plywood and is more consistent in properties with, for example, no hidden voids as is commonly the case with plywood.

Fixing to Studwork.
Fixings should generally be long enough to allow about 20mm penetration into the substrate or have an overall length of about 2.5 times the panel thickness, whichever is the greater. Parallel core screws should be used because they have greater holding power than conventional tapered wood screws. Drill pilot holes for all screw fixing. Typically, the holes should be 85 to 90% of the screw core diameter. Fixings into the board face should not be within 8mm of edges and 25 mm of the corners. In environments with typical humidity and temperature conditions, it is recommended that when fixing adjoining square edged panels, that a 3mm gap should be left at all edges of each panel. Nailing the boards to the studwork is also an option, but in this instance screwing was the preferred option.

Durgun Lift and Lock, Drywall Lifting Tool. Durgun Lift and Lock, Drywall Lifting Tool

This is a must-have tool for anyone working alone, trying to install heavy OSB panels. It's very easy to slip this under a corner and lift the panel while checking for flush fit, plumb and square. Your hands are free to position the piece while holding a square or level. Once you have it positioned, simply lift your foot and it stays, ready for screwing.
It's great for doors too. Easy to lift and hold the door for installation or holds the door open and stable for installation of new locks, doorknobs, etc.

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Details of Installation.
13th August 2015..
11 Sheets of OSB (for wall sheathing), and 2 sheets of insulation board (for partition wall), and some replacement roof ties delivered. All from Travis Perkins

OSB & insulation board delivered 13th August 2015. OSB & Insulation Delivered 13th August 2015.

Insulation board was for the partition studwork. Insulation for the wall studwork was ordered from a different company as Travis Perkins did not stock the required thickness.

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Moving a sheet of OSB using a skateboard, 13th August 2015. Moving an OSB Board, 13th August 2015.

Sheets of 18mm thick (1,220mm x 2,440mm) OSB individually weigh 34kg and two people should be on hand to move each sheet. However, one easy way for one person to move a sheet is to use an old skateboard, as shown here.

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Tools for attaching the OSB wall sheathing. OSB Techniques & Tools.

The 18mm thick OSB boards were cut to size using a jigsaw. For fixing the boards to the studwork, I preferred not to use nails but to screw the boards in position using parellel-sided 5mm diameter woodscrews, 60mm long for the 70mm thick studs of the partition wall and 50mm long for the 45mm thick studs on the walls. The pilot holes for the screws were pre-drilled to a diameter of 4mm. See below for more details.

The photograph shows a selection of the tools used in the installation including the drill, screws, drill-bits and the Durgun board lifter.

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The Durgun Board Lifter in use, supporting an OSB board. Using the Durgun Board Lifter.

The OSB board is held in the correct vertical position with the Durgun Board Lifter. The board's correct lateral position is achieved by abutting the vertical edge against several temporary positioning nails driven into the centre line of the vertical stud.

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Diagram showing how the OSB sheathing was fixed to the studwork. Attaching the OSB Sheathing.

Adjacent boards had a 3mm gap between them and a similar gap at the top and bottom of each board to allow for contraction & expansion due to changes in humidity. I preferred not to use nails but to screw the boards in position using 5mm diameter, parallel-sided woodscrews, 60mm long for the 70mm thick studs of the partition wall and 50mm long for the 45mm thick studs on the walls. The holes were pre-drilled to a diameter of 4mm. Screw intervals were at the recommended 150mm intervals along all edges of the boards and, for mid board vertical studs, the screws were at 300mm intervals. 54 fixing screws were used per full OSB board.

NOTE. The insulation boards in the interstices of the studwork, and the overlying polythene vapour barrier have been omitted from this diagram for clarity. The OSB boards are shown as translucent ghosts to reveal the position of the underlying wooden stud framework.

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Two photographs showing the positioning of adjacent OSB boards. Two Photographs Showing the Positioning of Adjacent OSB Boards.

The right photograph shows the the first OSB board butted up against the positioning nails driven into the centre line of the vertical stud. The second (left) photograph shows the second board butted up against the nails on the other side of the stud and both boards have been screwed in position, with the nails ensuring a 3mm expansion gap between the boards. The positioning nails were then removed.

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The first OSB board erected, 3rd September 2015. Erection of the First OSB Board, 3rd September 2015.

The first OSB sheet, encompassing the new partition doorway, was cut to size and screwed in position. Work started on the exterior of the partition stud wall whilst waiting for some additional wall insulation board to be delivered.

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General view of completed sheathing, 23rd October 2015.

Completed Sheathing (1), 23rd October 2015
Workshop showing completed sheathing, window and electrical sockets.

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General view of completed sheathing, 23rd October 2015.

Completed Sheathing (2), 23rd October 2015
Workshop showing completed sheathing, door, lighting and electrical sockets.

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